BienCheck pillar guide
Buying an apartment without getting burned
Written by Mathieu Delranc
Founder of BienCheck · View author profile
An apartment is never just four walls. It's a building, a neighbourhood, neighbours upstairs, charges that land every quarter and an EPC rating that decides your heating bill for the next decade. Too many buyers sign because they fell for the kitchen and the light, then find out six months later that the HOA is a mess, the reserve fund is empty or the F rating is killing the resale value.
This guide is everything we'd check ourselves before making an offer. No fluff, no theory. Concrete reflexes, the right questions to ask the agent, the documents to demand and the real negotiation margins depending on what you find on the visit.
Why an apartment isn't a standard property
When you buy an apartment, you're buying two things at once. Your private lot, what's yours alone, and a share of the building, what's shared. The shared part is the roof, the facade, the lift, the boiler room, the risers, sometimes even heating and hot water. All of it ages and eventually costs serious money to fix.
Your comfort, your monthly charges and the future value of your flat depend just as much on the building as on the flat itself. A badly-run HOA can turn a great deal into a money pit. A well-run one justifies a higher price per m² and pays back at resale.
That's why buying an apartment needs two checklists, not one. One for the flat, one for the HOA. Most buyers skip the second and pay for it later.
The essential checks before signing
Start with what you can see. On the visit, look past the staging. You're buying volume, walls, services, light. The furniture leaves with the seller. The cracked load-bearing wall stays.
- Orientation. Pure north in winter means heating bills going up and grim light all year. Check when the sun actually hits the living room, not just on the day of the visit.
- Floor and lift. No lift above the 3rd floor kills liquidity at resale. Ground floor needs a careful look at view, privacy and noise.
- Walls and ceilings. Stair-pattern cracks, damp stains on ceilings, warped parquet near windows, those are signals of leaks or settlement that need digging into.
- Windows. Single glazing or old double glazing means noise and cold. Full window replacement runs £550 to £1,100 per window depending on size and rating.
- Electrics and plumbing. A board with no RCD, fabric-wrapped cables, those cost hundreds or thousands to fix. Same for lead piping.
- Heating. Individual or collective, gas, electric, heat pump, oil. Annual cost can vary fourfold between energy sources and insulation levels.
- Balconies and terraces. Waterproofing redone recently or not, railings up to code, floor that holds water. Redoing waterproofing costs several thousand euros.
The HOA, what changes everything
Always ask for the last three AGM minutes, the maintenance log, the HOA rules, the dated statement and the long-term works plan. Without those documents, you're buying blind.
In the minutes, look for three things. First, works voted but not yet billed, those land on you if you sign. Second, works discussed but not voted, they'll come back. Third, the mood of the AGM. Three quarters of votes against everything, ongoing legal cases, large unpaid charges? Walk away or negotiate very hard.
Check the reserve fund. An HOA with 5 to 10 % of the last annual budget in reserve is healthy. An HOA at zero will call for cash within two years. The unpaid-to-called charges ratio should stay under 10 %. Above that, the HOA runs on fumes and any major issue becomes a crisis.
EPC, your bill for the next ten years
The EPC isn't a formality anymore. Under French Climate Law, thermal sieves (F and G) are being phased out of the rental market, and resale prices already reflect it. An E isn't a sieve, but the market is starting to penalise those too.
Concretely, an F-rated 3-room flat in Paris can mean €2,500 to €3,500 of heating per year, against €700 to €1,100 on a C. Over ten years, that's €20,000 of difference, before counting the works needed to move from F to D that the market will eventually demand.
If you buy an F or a G, negotiate accordingly. The real margin sits between 8 and 18 % of the asking price depending on the local market, and it's defensible in black and white with the EPC in hand.
Neighbours, noise, environment
Come back at a different time. Evening, weekend, a rainy day. A quiet street at 11am on a Tuesday can turn into an open-air bar on Friday night. An upstairs neighbour working from home on visit day can host loud friends every weekend.
Check Géorisques (the French government risk portal) before signing. Flood, clay shrinkage, seismic, radon, industrial sites. All public, all free. A Blue or Red flood zone changes your insurance premium and your resale.
Finally, check the local plan and any upcoming developments. A new building going up in front of your balcony in two years is known at the town hall well before you sign.
Pricing it properly
The price per m² the agent quotes isn't the market price. It's a listing price, often inflated 5 to 12 % to absorb negotiation. The real price sits in the last comparable sales, available in Etalab's public DVF database.
Look at sales in the last 12 months in the same area, at comparable size and standard. Adjust for floor, orientation, EPC, lift, outside space, parking. You'll land on a realistic range.
If the asking price is 15 % above your upper bound, either the agent is overpricing or the flat has an edge you haven't spotted yet. Ask for the listing history, how long it's been on the market and the price drops. The longer it sits, the wider the margin.
Negotiation playbook
Negotiating isn't humiliating the seller. It's defending your price with facts. Your best levers, in order: a poor EPC, works voted at AGM, visible technical defects (windows, electrics, waterproofing), an ad that's been up for over three months, DVF comparables clearly lower.
Put your offer in writing, with a short numbers-backed argument. Sellers get plenty of vague oral offers. A structured, defended offer changes the dynamic. If the first offer is refused, don't raise it straight away. Give it 48 to 72 hours. The market argues for you.
The 12 most common mistakes
We see these every day in BienCheck reports. Most could've been avoided by asking three more questions before signing.
- 1
Signing after one visit
You had a crush, the agent pushed, you signed. Always go back at least once, at a different time, ideally alone.
- 2
Ignoring the EPC
An F or G hits hard at resale and runs up heating bills. Factoring it in isn't optional.
- 3
Skipping the AGM minutes
A €35,000 facade renovation voted three months before you sign lands on you. Always ask for the last three minutes.
- 4
Forgetting the reserve fund
An HOA at zero will call for cash fast. Check the amount and the unpaid charges ratio.
- 5
Underestimating works
A new kitchen doesn't cost €5,000. A full bathroom isn't €3,000. Get two quotes before signing if you're planning real work.
- 6
Ignoring noise
Local bar, school, tram, ring road. Noise doesn't show in photos. Go back several times.
- 7
Taking the agent at their word
The agent works for the seller. Anything they say is unverifiable unless it's written into the offer.
- 8
Skipping Géorisques
Flood, clay, seismic, radon, industrial. Free to check and can change your mind.
- 9
Not comparing with recent DVF
The neighbourhood price per m² on big portals is a biased average. DVF gives the price actually signed.
- 10
Negotiating orally
A written, argued offer beats a vague phone call. And it leaves a trace.
- 11
Going to compromis without clauses
Precise mortgage clause, planning clause, HOA clause with no major works voted. A neutral notary writes these properly.
- 12
Underestimating side costs
Notary fees, council tax, charges, insurance, moving, entry works. Real cost often exceeds 12 % of the asking price.
Hidden costs to plan for
Beyond the purchase price, these are the lines people forget in an apartment budget. Orders of magnitude for an average property in metropolitan France in 2026. Adjust for your market.
| Item | Range | Watch out for |
|---|---|---|
| Notary fees | 7 to 8 % of price (existing) | 2 to 3 % on new builds. Calculated on price excluding furniture. |
| Council tax (taxe foncière) | €600 to €2,500 a year | Very local. Ask for the seller's tax notice. |
| HOA charges | €25 to €60 per m² per year | Higher with lift, concierge, collective heating, pool. |
| Entry works | €2,000 to €30,000 | Paint, floors, kitchen, bathroom. Get two quotes if it's a real project. |
| Voted but unbilled works | Variable | Check works voted at AGM but not yet invoiced. |
| Home insurance | €150 to €450 a year | Higher in risk zones (flood, theft). |
| Moving | €600 to €3,500 | Depending on volume, distance, floor, lift. |
| Diagnostics and expertise | €0 to €800 | Most are paid by the seller. A counter-expertise is sometimes worth it. |
How BienCheck helps
We built BienCheck to do the work no buyer has time to do alone. Here's what you get when you run an analysis on the flat you're eyeing.
Free analysis in minutes
Score out of 100, 3 strengths, 3 alerts, price coherence. No strings.
Full Premium report
10 detailed sections, quantified negotiation margin, real cost over 10 years, PDF export.
See a sample reportRisk analysis
Automatic cross-check with Géorisques: flood, clay, seismic, radon, industrial.
See covered risksEnergy analysis
EPC reading, ten-year bill projection, alerts on thermal sieves.
Understand your EPC
Apartment buyer FAQ
Should you buy or rent an apartment?+
Buying makes sense once you'll stay 5 to 7 years minimum and your monthly payment stays under 30 to 35 % of net income. Below that, renting and saving alongside often wins.
What's the best floor?+
2nd or 3rd in a no-lift building, 4th to 6th with a lift, those are the most liquid floors. Ground floor negotiates lower. Top floor gains value if it's bright and quiet.
How many visits before signing?+
Three minimum if possible. One to discover, one to confirm (different time of day), one with a friend or pro to clear the last doubts.
How do you vet the HOA?+
Ask for the last three AGM minutes, the maintenance log, the rules, the dated statement and the long-term works plan. Read it all, or have it read.
Is the EPC really reliable?+
Not always. Since 2024 the method is tighter, but gaps exist. Ask for the assessor's technical sheet and cross-check with the seller's real bills.
Can you negotiate on a new build?+
Less easily, especially early in the launch. But late in the marketing phase, developers often drop 3 to 8 % or throw in the kitchen, reduced notary fees, a parking space.
What if the AGM votes big works after the offer?+
If your offer has a clear HOA clause, you can renegotiate or walk. Without it, works voted before the notarial signing land on you.
What does an apartment really cost to own?+
Sum the monthly payment + charges + council tax + smoothed works + insurance. A €250k 3-room at 4 % over 25 years runs €1,700 to €1,900 per month all in, before surprises.
Should you buy a fixer-upper?+
Often yes if you have time, cash and a good tradesperson. You pay less per m², qualify for grants and pick up value as soon as works finish.
What margin can you expect?+
In 2026, on the existing market outside tight zones, average margin is 4 to 8 %. With defects (EPC F, works, bad orientation) or a stale ad, 10 to 15 % is realistic.
What to look at in the charges?+
Cost per m², the breakdown (heating, concierge, lift, maintenance), recent and upcoming works, and unpaid charges by other owners.
Ground floor, good or bad idea?+
Good if you live there and accept the discount. Bad if you plan to resell fast. Ground floor negotiates 8 to 15 % lower but stays less liquid.
How much deposit minimum?+
10 % of price to cover at least notary fees. 15 to 20 % materially improves your rate and your margin.
Worth using a broker?+
Often yes. A good broker saves 0.2 to 0.5 % on the rate, that's thousands over the term. Just make sure they're independent, not tied to one bank.
How to check for easements?+
Ask the seller for the cadastral extract and the HOA rules. The notary also checks published easements at the offer stage.
What if you find a defect after signing?+
If the seller knowingly hid it, you can sue for hidden defects within two years. Document immediately with photos, invoices, written exchanges.
Glossary
- Compromis de vente
- Pre-contract signed by buyer and seller, binding both under suspensive clauses (loan, planning).
- Promesse de vente
- Variant where only the seller commits to sell, against a deposit paid by the buyer.
- Suspensive clause
- Condition that must be met for the sale to go through. The classic one is mortgage approval.
- EPC (DPE)
- Energy performance certificate, A to G rating based on theoretical consumption and CO2 emissions.
- GHG (GES)
- Greenhouse gas emissions of the home, in kg CO2 per m² per year.
- HOA charges
- Money paid to the syndic to maintain common areas, pay the concierge, lift, collective heating.
- Reserve fund
- HOA savings, mandatory since ALUR law, earmarked for upcoming major works.
- Syndic
- Person or company managing the HOA: voting works, collecting charges, enforcing rules.
- HOA rules
- Founding document describing common and private areas, rules of life and each owner's share.
- Tantièmes
- Each owner's share in charges and decisions, expressed in thousandths.
- État daté
- Document from the syndic to the notary detailing what the seller owes the HOA.
- Long-term works plan
- Mandatory for HOAs over 15 years old, listing planned works over 10 years.
- AGM
- Annual general meeting of co-owners, where budget, works and rule changes get voted.
- AGM minutes
- Written record of decisions taken at the AGM.
- DVF
- Etalab's public free database listing every real estate sale signed in France.
- Géorisques
- French government portal cross-referencing natural and technological risks at a given address.
- Notary fees
- Misnamed: mostly state transfer duties. The notary keeps a minor share.
- Taxe foncière
- Annual local property tax paid by the owner, based on cadastral rental value and the commune's rate.
- Carrez law
- Defines the private surface of an HOA lot, excluding walls, partitions, stairs, ducts, recesses.
- Hidden defects
- Non-apparent defects at sale time, making the property unfit for use. Recourse possible within two years.
- ERP
- State of risks and pollution, mandatory attachment to the offer, summing up known risks at the address.
- Climate Law
- Law progressively banning the rental of thermal sieves (G in 2025, F in 2028, E in 2034).
Going further
A few BienCheck resources that complement this guide.
- The BienCheck Premium reportWhat a full report looks like and what's inside, section by section.
- Understanding the EPCRating, kWh/m², GHG, thermal sieves. What it changes for your purchase.
- Natural and technological risksFlood, clay, seismic, radon, industrial. How to know before signing.
- Buying a houseThe pillar guide for houses: roof, structure, land, easements.
- Negotiating a propertyConcrete levers to push the price down without spooking the seller.
- Understanding a condoAGM minutes, reserve fund, syndic, charges. What to know before signing.
- Succeeding at buy-to-letNet yield, vacancy, tax. How an apartment stacks up as a rental.
- DVF sourcesReal estate sales signed in France, by address, free and public.
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