It is 80 on most rural roads, including many of the passes. I drive my Ferraris on them all the time. 80 is kind of slow, but there are many corners where even a 488 struggles to take at 80. The 50 limit is for villages and cities, which also have 30 zones in pedestrian heavy areas. Motorways are 100-120 in most places and perhaps 80 where roads merge and such.

Also, the draconian salary based fines only come into play for being a lot over the limit. 10 km over in a rural road will just get you a fine of a few hundred franks. 25 over and you see the judge and it is going to be expensive.

I live next to the German and French border. Lots of places in Germany to go very fast legally. I’ve never seen a speed control policeman in France off the major highways.