In the US, there are various websites for checking service availability based on zip code. You can fairly easily find local ISPs in a region and then use their own service checker to see if service is available at a specific address -- in other words, the same method you'd use if you already lived there and wanted to order service.

Can't speak for France but in Germany, you can usually check on each ISP's website what their coverage for a specific street address is. It's one of the things I always do when I look for a new home.

Depends on which country you live in.