Legal, illegal, and really illegal.
Above: legal parking spaces. Good luck finding one of those.
totally normal (unless the other driver is actually in the car you're bumping).
Double-parking is illegal, but everybody does it. There are parts of town where you completely expect it. This is on avenue Montaigne, part of the Golden Triangle of glamorous jet-set stores. (I once saw J.K. Rowling crossing the street here during the January sales.) Voituriers, or car valets, normally have to double-park at least some of their cars.
What is really illegal? Only a few things. Parisians are better than you might expect about not parking in a handicap space. The other really illegal thing is to park in a crosswalk and Parisians avoid this if they possibly can. (Crosswalks are called passages cloutés, nailed passages, in France, because the old ones look like this:)
Unless they really need a parking spot.