When buying your French property and you hear a reference to possible 'vices cachés' (literally 'hidden vices') no-one is casting doubts about about the morals of the vendor! The reference is in fact to possible hidden defects in the building structure, that may or may not be known to the owner - and if known should be disclosed to the buyer.
When a property is visited by a potential buyer or, more importantly by an estate who is thinking of taking it onto his books, obvious defects should be relatively simple to detect. These can include electrical wiring that is not up to current standards, defective plumbing and gas installations, and potentially dangerous renovations that have, for example, involved removing a supporting wall. If these are present, then there is a case for negotiating a reduction in the asking price in order to put things right, or you can walk away from the transaction and look elsewhere.
What are more problematic are hidden defects which are genuinely not known to the owner and not readily detectable by a casual inspection; and defects that the owner is aware of but tries to conceal from a potential buyer. Proving a vendor's bad faith may prove difficult and there is no easy way of determining in law whether he knew or not about the hidden defects.
In case of doubt it is wise to commission an expert survey (not always a 100% guarantee) particularly in the case of older buildings, and if necessary obtain estimates for making good any defects discovered, as a basis for negotiating a price reduction. Otherwise you buy the property in the state in which you found it and have little recourse in the event that hidden defects are later discovered.
Buildings that are held in co-ownership ('co-propriété) such as apartments and houses on some estates ('lotissements') are obliged to keep a record of works and renovations carried out, and you should be able to consult these. You will also get an idea of the likelihood - and cost - of any future works (such as renovating or replacing the lift) that will fall as an extra cost on the co-owners, in proportion to their share in the common parts.
In the case of new-build houses or apartments, they are covered by the developer's required guarantees - up to 10 years in the case of the building's structure, and one or two years for equipment installed.
In all cases it pays to take your time before agreeing to buy a property, making one or more return visits if necessary, including checking the neighbourhood. A noisy adjacent factory or a school playground maybe be silent at weekends or during holidays, and need to be visited on a normal weekday. Cafés and bars that may look attractive by day can become a disco nightmare after dark. It is in your interest to check, as neither the vendor nor the agent is obliged to point out anything that might discourage you from buying!