I am renting an apartment in France and the owner is requesting I send the deposit and, 30 days prior, the balance of the payment by check or wire transfer, in Euros. He has provided a French postal address as well as RIB, BIC, and IBAN numbers. As I understand it, bank transfers have pretty much replaced checks for transactions like this one, so the fact that the owner (a sole proprietor) is not accepting credit cards is not suspicious to me. So, how should I send this payment?
A wire transfer is inherently unreliable, so much so that Western Union money transfers have become the preferred scam method in London for people taking 'deposits' on apartments that don't exist! (the joys of using Gumtree).
A cheque at least is traceable, but then you have to put up a fight to get the money back if need be, and it's hard to argue, because after all, you sent him the cheque!
It's pretty rare that people require payment upfront, although to be fair I did that for a place I rented last year in Australia, which was fine (AirBnb). At least that was a lot easier to check their references.
Consider reading something like this -a guide to spotting a scam when renting. Have you read reviews of the place? Know anyone local who can confirm that it exists?
It's understandable that he's not accepting credit cards, he may get charged extra for accepting them.
Finally, ask if he'd accept a deposit for now, and the full amount later - that at least minimises your loss if it is a scam.