BienCheck pillar guide

Understanding a condo before you buy

14 min read Updated 13 June 2026 BienCheck

Written by Mathieu Delranc

Founder of BienCheck · View author profile

Buying in a condo means joining a small company you'll own a share of. You'll vote, you'll pay your share, you'll live with the majority's decisions. The quality of that company matters as much as the quality of the flat itself. A well-run condo grows in value. A badly-run one drains your wallet and blocks the works you need.

Too many buyers sign because they liked the kitchen and skip the AGM minutes. Six months later, they discover a €18,000 facade job, an empty reserve fund or a managing agent in legal trouble. This guide is what we look at, every time, on every condo, before even analysing the flat.

What a condo really is

A condo is a building split into lots. Each lot has an owner, and all shared parts (roof, facade, lift, hall, stairs, risers) belong to all owners in proportion to their shares. The condo rules set what's private, what's shared, and how collective life runs.

When you buy a lot, you buy two inseparable things: your flat and a share of the building. You can't decouple them. If the condo votes tomorrow to redo the roof for €120,000, your share comes due whether you wanted it or not.

That's why we treat the condo as a hidden investment inside your purchase. You don't buy it separately, but you inherit it in full. Better know what you're walking into.

The 7 documents to demand before signing

The seller or the agent must hand these over before the compromis. If they drag their feet, push. If they refuse, that's a signal on its own.

  • The condo rules (règlement). Founding document describing lots, shares, common parts and collective rules. Read it through at least once.
  • The last 3 AGM minutes. The mood, the votes, the conflicts, the upcoming works. Read all three, not one.
  • The maintenance log. Lists past works, costs, contractors. A blank or vague log means a condo that isn't being followed.
  • The long-term works plan. Mandatory for condos over 15 years old. Projects works for 10 years with costs and priority.
  • The dated statement. Notary document showing what the seller still owes the condo and what you'll inherit.
  • The DTG (technical diagnosis). Mandatory for condos over 10 years old. Full state of the building and an action plan.
  • The pre-dated statement. Simplified version handed over at promesse stage. Ask for it early to avoid a last-minute call for funds.

Reading AGM minutes in 10 minutes

AGM minutes often run 20 to 40 pages. You don't have time for all of it. Quick method: first, quorum and attendance. An AGM where only 30 % of shares show up is a disengaged condo, where decisions struggle to pass.

Next, look at votes against. If every major resolution passes by a hair with a hostile minority, blocking is coming. Recent legal challenges to minutes are a red flag.

Then the works. Voted and budgeted works fall on you if you sign after the vote. Discussed but not voted works will come back. Voted works funded from the reserve, check if the reserve covers them or if a top-up call is coming.

Finally, the any-other-business section. That's where you often learn about a recurring leak, a litigious neighbour, or a plan to sell off common space.

Charges, what's normal and what's not

Running charges pay for maintenance, cleaning, common-area electricity, the lift, the managing agent, insurance. Budget €25 to €35 per m² per year for a standard condo without services. €40 to €60 with lift, concierge, collective heating. Above €80, you're in high-end (pool, concierge, security).

Exceptional charges are the big works. They land as calls for funds, sometimes heavily. Ask for the last three years of exceptional calls. If the condo has called €8,000 of exceptional per lot in two years, it's catching up on backlog.

Watch for an unpaid-to-called ratio above 10 %. Beyond that, the condo runs on fumes and any breakdown becomes a crisis. The managing agent must give you that number, it's in the pre-dated statement.

Reserve fund and long-term plan

Since the ALUR law, the reserve fund is mandatory for condos over 5 years old. It must equal at least 5 % of the annual budget, ideally 10 to 15 % to absorb big works without pain. An empty fund means a condo about to ask you for cash the moment the boiler fails.

The long-term works plan projects everything to do over 10 years, with working cost estimates. Ask for it, read it. If a full roof replacement is planned in 3 years for €250,000, you know what's coming.

A condo claiming it has no long-term plan while being over 15 years old is breaking the law. Not fatal, but it means nobody's really steering long-term maintenance.

The managing agent and how to judge them

The managing agent is the condo's executive. They call AGMs, execute votes, manage the bank account, pay contractors, collect charges. Either professional (paid firm) or voluntary (an elected owner). Both can work.

To judge an agent, check regular AGMs (one per year minimum), respect of legal notice periods, recovery rate on unpaid charges, clarity of calls for funds, and budget transparency. An agent who replies within 48 hours is a good agent.

Professional agent fees sit between €180 and €350 per main lot per year, excluding special services. Above €400, it's expensive and worth renegotiating at renewal.

Voted works, upcoming works

Works voted at AGM are legally due from owners pro rata their shares. Basic rule: whoever owns at the time of the call pays. If you sign after the vote but before the call, it's on you, unless the compromis says otherwise.

It's negotiable. Insert a clause in the promesse transferring voted-but-uncalled works to the seller, or adjust the price accordingly. The notary drafts this cleanly.

Upcoming works not yet voted are a grey zone. If they're in the long-term plan and imminent, fold them into your negotiation. If only discussed, at least keep a mental reserve.

Red flags that should make you walk away

Some signals justify either walking or negotiating hard. An empty reserve fund despite an old building. An unpaid rate above 15 %. Several ongoing legal cases, especially against the agent. No AGM held in over a year. A blank or incoherent maintenance log.

Add an old condo rulebook never updated, repeated exceptional calls, or a managing agent changing every year. Each signal alone isn't fatal, but stacked up, you're buying a problem, not a flat.

The 12 most common mistakes

  1. 1

    Not reading AGM minutes

    The biggest miss possible. Every bomb is written there in black and white.

  2. 2

    Ignoring the reserve fund

    An empty fund means an imminent call. Always ask for the amount.

  3. 3

    Confusing running and exceptional charges

    The first are stable, the second land in bursts and can wreck a budget.

  4. 4

    Skipping unpaid rates

    A high unpaid rate means you'll pay for others.

  5. 5

    Underestimating an old lift

    Full overhaul runs €30k to €80k. Check age and maintenance.

  6. 6

    Forgetting collective heating

    Replacing a boiler is €60k to €200k for the condo.

  7. 7

    Not checking the DTG

    Technical diagnosis gives the full state of the building. Mandatory at 10 years.

  8. 8

    Ignoring the condo rules

    Restrictions on use, short-let, pets, professional use. It's all in there.

  9. 9

    Underestimating an upcoming facade job

    A full facade is €50k to €250k depending on size.

  10. 10

    Thinking you'll change agent easily

    Changing agent is voted at AGM. If the majority doesn't follow, you're stuck.

  11. 11

    Skipping common areas on the visit

    Dirty hall, broken letterboxes, dark stairs: symptoms of a badly-run condo.

  12. 12

    Forgetting the pre-dated statement

    It reveals what you'll inherit. Always ask early.

Hidden costs of a condo

Beyond running charges, here are the lines often forgotten. Ranges for a standard French condo in 2026. Adjust for your building.

ItemRangeWatch out for
Annual running charges€25 to €60 per m² per yearDepends on services (lift, concierge, heating).
Facade renovation€50,000 to €250,000Every 15 to 20 years. Share pro rata your tantièmes.
Roof replacement€30,000 to €150,000Every 25 to 40 years. More for flat roofs.
Lift modernisation€30,000 to €80,000Every 20 to 30 years. Mandatory on new standards.
Boiler replacement€60,000 to €200,000Every 25 to 30 years. Often a chance to switch to heat pump.
Water risers replacement€40,000 to €120,000Roughly every 40 years. Forces shutoffs.
Common-area electrical upgrade€10,000 to €40,000Depends on age, size, floors.
Professional agent fees€180 to €350 per lot per yearAbove that, renegotiate at renewal.

How BienCheck helps

Analysing a condo means cross-checking documents, time and experience. BienCheck does that work for you, at your pace.

  • Free analysis in minutes

    Score out of 100, condo alerts, sanity check of stated charges against the local market.

  • Full Premium report

    AGM minutes read, reserve fund, long-term plan, structural alerts, quantified negotiation margin.

    See a sample report
  • Market price data

    Price per m² against recent DVF sales in the area.

    Check DVF
  • Building risks

    Géorisques cross-checks flood, clay, seismic, radon, industrial at the exact address.

    See risks

Condo FAQ

What's a tantième?+

It's the unit measuring your share of the condo, usually expressed out of 10,000 or 1,000. It sets your share of charges and your voting power at AGM.

How many AGMs a year minimum?+

One per year, mandatory. A condo not holding one is in breach and that's a bad signal.

Is the reserve fund refunded at resale?+

No. Sums paid in stay with the condo. You leave them behind.

Can I refuse to pay voted works?+

No. Unless procedural defect or valid legal challenge, you must pay your share.

What if AGM votes big works after my compromis?+

If the condo clause is well drafted in the promesse, you can renegotiate or pull out. Otherwise, it's on you.

How much does a professional agent cost?+

€180 to €350 per main lot per year for base fees, excluding special services (transfers, disputes).

Can you become a voluntary agent?+

Yes, if you own a lot. Elected at AGM. It takes time, tools and specific insurance.

What's a DTG?+

Diagnostic technique global. Mandatory for condos over 10 years old. Full state of the building plus action plan.

How to check the unpaid rate?+

Ask for the pre-dated statement or the last three years' financial annexes. The agent must provide them.

Can a condo go bankrupt?+

Not like a company, but it can be placed under court administration if unpaids get out of hand. Avoid at all costs.

Can I renovate inside my flat without approval?+

Yes for private parts, except structural (load-bearing walls), facade, or use changes. Read the rules.

Can the condo rules ban short-let?+

Yes, if they ban short-term rental or impose strict residential use. Check before buying to let.

How big is a typical exceptional call?+

Depending on works and your share, between €500 and €15,000 per call. The long-term plan should give you a projection.

Which works pass by simple majority?+

Routine maintenance and legal compliance. Improvement or structural changes need a reinforced majority.

Who pays for a leak from common parts?+

The condo, via its insurance. But excess and claim hit the charges. Check the policy.

Is the maintenance log mandatory?+

Yes, since the SRU law of 2000. A condo without one is in breach.

Glossary

Condo (copropriété)
Building split into lots owned by several owners, with shared common parts.
Lot
Ownership unit including a private part (the flat) and a share of common parts.
Tantième
Unit measuring an owner's share, usually out of 10,000 or 1,000.
Share (quote-part)
Each owner's slice of charges and votes, proportional to their tantièmes.
AGM
Annual general meeting of owners, mandatory, where budget, works and rules are voted.
AGM minutes (PV)
Written record of decisions and votes at the meeting.
Managing agent (syndic)
Person or firm running the condo, elected at AGM, professional or voluntary.
Council of owners
Elected owner group assisting the agent and overseeing management.
Condo rules (règlement)
Founding document setting lots, shares, common parts and collective rules.
Dated statement (état daté)
Notary document detailing the seller's outstanding sums to the condo.
Pre-dated statement
Simplified version handed at promesse, essential before signing.
Reserve fund
Mandatory savings to fund upcoming big works, since the ALUR law.
Long-term works plan
10-year projection of works, mandatory for condos over 15 years old.
DTG
Diagnostic technique global, full state of the building, mandatory from 10 years old.
Maintenance log
Mandatory document listing all works and interventions on the building.
Running charges
Regular maintenance and operating costs, paid quarterly.
Exceptional charges
One-off calls for big voted works.
Call for funds
Payment request issued by the agent to cover planned spending.
Unpaids
Charges due but not paid by some owners, worth watching.
ALUR law
2014 law making the reserve fund and new transparency rules mandatory.
Absolute majority
Majority of all owners' votes, present or not, for certain votes.
Simple majority
Majority of votes expressed by owners present or represented.
Agent mandate
Contract binding agent to condo, usually renewed annually.
BienCheck tools

From guide to action

Guides explain. Tools decide. Run the analysis on your property or compare your options in two clicks.

Ready to analyse a condo?

Run your free BienCheck analysis. We read the key signals for you and hand back a score, alerts and an estimated negotiation margin.

Analyse a condo for free