You're probably not supposed to stop a car in those places, and when you do, you're supposed to stop on the road, never on the sidewalk. Steep fines for that in Belgium at least, though the odds of getting caught are slim.
It's illegal in the US to block the sidewalk with a car and it's one of the few things cities will actually enforce aggressively -- if they don't, they can be sued for discrimination under the Americans with Disabilities Act.
At least in San Francsico this is very rarely enforced. What I've seen professionally and personally is that cities will ticket the easy stuff. Street cleaning is at the top of that list followed by time-based red zones.
