Financial incentives do not make sense: having a car in Paris is already crazy expensive. During the 20 years I lived there, I cycled everywhere, and I had an almost weekly accident, always at the same three intersections -- cars running into stationary bikes, half the time openly on purpose (there is a bolo for a taxi driver for attempted manslaughter under my name: his plaque was unlegible on the camera, but him ac…
I've lived in Paris for 45+ years. The problem with bicycles is that they don't respect road signs or traffic lights, which irritate the hell out of everybody else. It's true that many car drivers are very aggressive towards bicycle riders, but what you fail to mention is that everyone cheers for the car and not the bike... Personnally I ride a motorcycle; it was stolen last year and so I used bikes for about a month…
I can cycle hard and sweat, or I can cycle gently and sweat very little. We don't have a shower in the office, but I don't cycle too hard to work, and change shirt when I get in. It's not a problem. On the way home, I cycle hard and have a shower.
I can stay completely dry when cycling by simply carrying waterproofs. I just make it routine to always have these. It's true that these make it a little sweatier, but a change of clothes solves this problem.
Cycling isn't going to be suitable for every journey. However, 15% is quite a small target when you think about all the little trips people need. Things like cheap electric cars can be useful for the remaining 85%.