Hi Gabby and welcome to the site.
I’d want to see everything working before I signed the CdV.
If they’re not prepared to turn things on to be checked you have to ask ‘why?’ ANd why such big discrepancies in area and tax?
If it were me, I’d walk away.
I’m afraid I agree with Brian there @gabby . It’s such an important purchase, unless you have a great deal of money you don’t mind throwing at it, I don’t think I’d take the risk of signing unless all the discrepancies were cleared up. There’s a big difference between non-functioning drawer handles and a possible lack of planning permission for an extension 
Stella - That’s right. The DDT report says they couldn’t check everything because the gas was turned off.
As for the m2, it’s a wild guess on our part about permits. We know they added on about 10 years ago. What else would cause such a huge difference in m2? When we mentioned the discrepancy and our guess to our notaire, they were a bit shocked and said they had no information that the house was ever expanded. They’re waiting to hear back from the seller’s notaire.
_Brian - Thanks for the welcome. We feel the same way, we want to see everything working. Yet we keep being told it’s not possible due to winterization and to just “check it before the final signing”. From everything I am reading, by then it’s too late.
AngelaR - Thanks, and you’re absolutely right. We can afford some broken door handles but the rest? 
One thing I’m not clear on, and sorry if this is a stupid question: Can we back out free and clear now, even though we haven’t signed the Compromis? No deposit paid yet but it would have to be transferred next week before the signing in two weeks. I know there’s a 10-day cooling-off period after the Compromis. But if we determine it’s a no-go now, why would we have to sign and then use the 10 days?
Must say… your situation sounds very similar to another forumite, who was faced with similar oddities re the property on offer quite recently…
Speak with your Notaire and then walk away… you’ve not signed anything, you’re not bound by anything.
This sort of thing (walking away) happens quite frequently… especially when there are oddities/unknowns about the property on offer.
There’s lots of good properties on the market… take your time and find one which is just what you want, free and clear with no waffling…
@Stella - Any chance you have a link to the other story? I would like to read it. We know someone else walked away from this house before, but we were told it was a mortgage problem. That would be an unreal coincidence if someone else on this forum was also looking at the house and decided to walk away!
Probably not the same property… but the advice still stands good.
Walk away.
Your intuition is telling you this.
The only exception would be if you are very rich, have fallen in love with the property, and you are willing and especially able, to pay absolutely any amount of money to fix the surprise your gut is telling you is surely waiting for you.
Almost every property will have something you weren’t told about that is negative or thing(s) to fix. Nothing is perfect. Unauthorised works that did not have planning permission are quite common. But the approach to this is really tightening up.
Do not.sign the compromis - that’s close enough to not being able to get out of it. Yes there are some escapes but they technical and onerous as the requirement to prove would be on you, to escape once you’ve signed.
You need to take your time to know the area then view a property ideally at the worst time of year and ideally test everything yourself at that time with the aid of any tradesmen needed. And have the compromis adjusted to protect you for anything you’ve not been able to verify to your satisfaction. You are the buyer, not them.
Too much doesn’t add up here, taxe f. is an old figure because they’ve been trying to sell it that long. Which would be unusual in the past year or 18 months or so.
Listen to your gut and walk away.
The discrepancy in the size of your potential property might not be as bad as first appears.
By way of example:
(a) My house was advertised by Leggetts at 171 m2;
(b) On the cadastral it is 183 m2;
(c) Our architect sized it at over 200 m2
(d) on a tax document (that I can’t locate now) the size is 330 m2.
However the 330m2 includes a terrace, conservatory, and various outbuilding all of which appear to
be taxed at different rates.
In conclusion, I would advise further investigation.
The lower figure may be “espace habitable”, whereas the higher may be the plan floor area. Clearly estate agents like to tell you higher figures, whereas planning & tax matters work to a different formula.
Elsewhere on this site I posted this, which explains what is defined as habitable or not…
It is really up to the vendor to prove everything is in order to your satisfaction - if they are not prepared to do this ask yourself why.
If you are not 100% happy look elsewhere.
Thank you everyone for the replies. I’ll try to get to each of them. Since I’m new I can’t tag everyone.
Stella - Thanks for the link, some good stuff in there. Yes, there are some similar warning signs. The big difference is that these are the original owners/builders of the property. In theory all the paperwork should be easy. We’ve seen receipts from a lot of the things and they spared no expense for quality. So it seems bizarre they would not have had all the permits.
We don’t know for sure there wasn’t planning permission. Let’s assume for a moment there wasn’t. What is involved in “Rétrospective planning” either for the seller or for us? The extension is 10ish years old so I think it’s beyond any warranty or whatever.
KarenLot - I’d like to think we visited at the worst times of the year. It was raining and cold in October, and foggy, cold and windy in February. You raise an interesting point about the tax fonciere. Would it make sense to go up by 10% in roughly 2.5 years? As far as we know it’s only been on the market for a year.
Nigel - Thanks for the example. We don’t have that level of detail. Maybe we don’t know where to look. Any tips? The ad says 200+ m2 habitable but has an asterisk that it’s not legally binding. The cadastral printout doesn’t show m2 for anything. The “releve de proprietere” doesn’t show m2 for the house, only the land.
Badger - Thanks. They say 200 m2 habitable and all floors have 1.8 m or higher ceilings (including the finished basement). We have measurements of the rooms from the agent. If we subtract the basement, we’re within 5 m2 of the “official” 140. But then the advertised 4 bedrooms doesn’t match, because the bedroom in the basement wouldn’t count. I think.
JaneJones mentioned in the other thread about an H2 form. Is that something we can ask for, to see whether the extension was declared to the tax authority? It seems like the taxes go up a little bit each year anyway.
We’re close to walking away but we feel like we should keep learning the ropes for another week before pulling the plug. As the saying goes, we don’t know what we don’t know. Any other suggestions on documents to ask for, things to see, etc. are appreciated. Who knows, the paperwork could all magically fall into line on time, but somehow I doubt it. 
You need to go to:
https://app.dvf.etalab.gouv.fr/
and then fill in the Department, Commune and Cadastral boxes.
You should then see a map with the Cadastral sections.
On the RHS of the screen should give details of the last sale:
date, price, house size, and land.
It may well be that your property plot consists of more than one cadastral section.
Not advice (sorry), but a question - was it a “mainly british clientele” targeted agency with a british agent, and are the vendors british?
My advice would be in the first place is to get the agent to get everything checked , and if they cant or wont, walk away. The notaire is trying to CYA by saying "en état " and you shouldn’t accept this unless you are happy about it.
How come the details are not clear…
This property has already had one “nearly-buyer”, who finally backed out… (the one that we know of).
I would have expected the Seller to have already got all the details of the Property together, well organized…
Ready, Steady GO… for when the next Buyer came along… instead it seems just waffle and more waffle.
Rather odd, in my book.
@Nigel-at-BUF-House - We’ve been on that site, but the property hasn’t sold in the last 5 years. It’s still the owners from 2002. Unless I’m missing something. Other properties in the area are blue or pink and can be clicked for information. There aren’t many sales in the area in the last 5 years either. I guess people like where they are? We also got the cadastral plan from this site, but it doesn’t tell anything about the house size: https://www.cadastre.gouv.fr/
@Mark - There’s British or at least “foreigner” all over it as you describe. 
Although we picked a French notaire. We suspect it must have been targeted to Brits or other unsuspecting foreigners. Otherwise why would it be on the market for a year without any local snapping it up?
I recently waited the 6 weeks between making an offre d’achat on a property and signing the promesse de vente at the notaires( to be able to withdraw from it legally,using the 10 days retraction period)This was a sale without an estate agent
Although I had had reservations before the 6weeks I realised that the offre d’achat is legally binding unless you put in a withdrawal clause or reserve(which I hadn’t) and felt bad for the vendors waiting all that time.(In fairness I didnt receive all the diagnostics and copropriete regs etc until 36hrs before the signing and a few more issues persuaded me I was doing the right thing)
But I do wonder why the offre d’achat is said to be legally binding if you can get out of it at the promesse or compromis stage?
I would not hesitate to tell the vendors in the future if I wanted to withdraw before the promesse de vente but would make sure I put in the clause "subject to – in the offre d’achat in the first place.
There is such pressure on property in my area at the moment that people are making offers more rapidly than they used to and therefore more likely to withdraw when they have reflected properly
Good luck with whatever you decide
I think its only legally binding concerning the price (agreed between buyers and sellers)
We were told the offer letter is legally binding, but sellers almost never bother to go to court to force a sale. It costs them more in the long run and the house remains unsold while they fight. We do have an “out” clause in the offer letter, which states the offer is null and void if a Compromis is not signed within 30 days. I have to say, the buyer seems pretty well protected in France.
Oops, missed a post from Stella - you’re right on waffle, waffle. We were pleased to get the DDT quickly since there was a previous buyer. But since then it’s moving at a snail’s pace to get information from the seller’s notaire.
I’m a bit more aware now having been through the proceedure for the first time on my own and hopefully will learn from my mistakes if I can find a next time!!(One of the occasions that an estate agent would have come in useful)
The point of visiting at bad times of the year isn’t just to see if you still like the house and its surroundings and see it in worse weather.
It’s to test things in the house work sufficiently in those conditions. What’s their story about why they won’t prove the gas stuff work? What did your surveyor informally say about this? In London I always asked a surveyor to give me an informal comment about anything they put in the report they’d not got access to, for instance. Saying something wasn’t accessible or couldn’t be tested on the day is a cover for the surveyor and I would expect the vendor to have a good excuse if something key can’t be accessed or tested.
Why do they say they’re selling? Have you visited the mairie to have a “general” chat? This was what started a chain that let us find out our seller had lied to us on a key point.