Yes, many people think that but for my part, I have really noticed a big decrease in speeding since these fixed speed cameras have been put into place, in the last 15 years or so.

It was not unusual to have people drive 150 km/h or so on the 110 speedways I was taking then, or 110 on the 90 countryside roads. Nowadays it seems like only few people break speed limits by such margins. In Belgium however (where I live now) there are speedcams as well but I notice a lot more speeding.

I think the difference is at least partly due to the points permit. French drivers get a total of 12 points and lose at least 2 points from any speeding, while Belgians only get a fine, which probably doesn't give a lot of incentive to people who have enough money to just pay the fine.