[victorNicollet]

In France, it doesn't even have to be a cash offer (although it mustn't have any contingencies beyond "buyer will get a loan"). This is mostly because most people in France don't have that kind of cash lying around, so if you only accept cash offers the rule applies to almost no one.

Of course, sellers prefer an asking price offer in cash, rather than with a loan that might be denied, so there's usually some (illegal) leeway if offers are received by mail. If you intend to make an offer contingent on a loan, make sure you print out the offer and bring it with you, and have the seller sign your copy. This lets you answer "There was another offer before you" with "That's not what it says on the paper you signed".