Except when driven by stupid or/and drunk persons, cars and other 4-wheeled vehicles stay out of the bus lanes, in France. The vast majority of people follows the traffic regulations, here, please don't extrapolate a generic behavior from the one of an imbecile

In fact, the real problem with bus lanes, for me, is that they are sometimes common to buses and (non-motorized) bikes, which can be a bit dangerous for cyclists. All the more as some bus drivers drive fast, due to their empty lane...