Have to agree.
The only thing more inconsistent than FR hand luggage policy is the weather! Have travelled many times with backpack on and lugging laptop bag. Sometimes got away with it, sometimes not. Best plan is to try ensure that all really valuable stuff in your laptop bag, so if the agents get shirty, then can simply check in the day pack. Beware also of the 15kg baggage allowance, which is also very variably applied. Got hit for 60 quid at Hahn last time - almost every passenger was shelling out extra dough. Kind of hurt though, since we had only paid about 40 pounds for the tickets..... Rulz are rulz though.