The rule is very clear: door handles, bulb holders and lightbulbs, window panes, doors, etc, are all part of the house, as are all things attached to the walls (so basically requiring more than a simple screwdriver to remove). This is stated in most compromis de vente.
That said, things happen very frequently. A notaire friend of mine told me that in the 1990s, so before mobile phones with cameras, he sold a lovely 17thC Norman manor near Cabourg. Parisian buyers visited once, loved it, signed a compromis with him and the sellers, and left it at that until the day of the signature finale, the Acte de vente. They visited again with the owners an hour before, as is customary, to check that everything was fine, that there had been no flooding, no fire, no demolitions etc.
So all went to the notaire’s office, signed the deed , buyers got keys, sellers got money, Notaire got tired.
The buyers proceeded to their new abode, and found that in the 2 hours that had just elapsed, all the carved doors , bronze fittings, mouldings, panels, wrought iron gate, had been removed.
They immediately phoned the notaire, who phoned the sellers, who claimed they didn’t know anything about this and denied the existence of said carvings, doors , mouldings etc.
A very sorry notaire told his buyers that the only way out was to go to court, and see what would happen.
A year later, the buyers lost the case for lack of proof, the ad had been seen in Ouest-France with a single photo of the outside, and the notaire himself had never seen the property.
This isn’t the end! The clerk had a wonderful idea: there weren’t that many 17thC manors in the region, and maybe, just maybe, one of those decoration magazines had published an article about it in the past. So they contacted all the magazines (Maison et travaux, etc) and bingo, they found out that the house had been featured in an article with accurate descriptions and many photos.
Back to court, buyer’s first claim matched exactly the description of lost architectural features, and they won the second case. It turned out the sellers had sold everything to antique dealers, and had a team ready to remove everything from the house in record time.
I don’t know what happened next, either the sale was cancelled or the sellers had to reimburse a substancial amount of money.
So whenever you visit a house, make sure you take lots and lots of photos…