Well there's the law, but there is the interpretation of the law. A photographer, recently had is pictures from the Parisian Metro challenged and at the end he did win, when shooting in the Metro isn't allowed and shooting people neither !
The real aim of these laws are not to find yourself, your kids, you family, on a commercial poster (publicity) or worse, on yoghurt packs sold all over the world. Most Parisian don't care, unless they are not with their legit spouse or should be at work (many examples with TV viewing public at Roland Garros tennis event) :-)
Most people don't care, but some do - I have been asked just about politely by people in public places if I was photographing them (I wasn't). There
is a sense among the French that a man ought to be able to have a quiet drink on a cafe terrace with his mistress without worrying about being photographed.
It is also true that the law is vague and the French courts have not clarified it. There was the case of Francois-Marie Banier and his book
Perdre le Tete; a woman who was, IIRC, a fashion publicist was shown in the book without her consent and she sued. The court's decision said that the public interest in artistic creation outweighed her right to control her image, but the judges hinted that a key factor was that the photographs were taken during her work as a fashion publicist, and someone whose job is to create publicity cannot complain when they succeed. (The parallel here with the UK courts' decision in the case of JK Rowling's son is clear). But then there was the case of Yan Morvan and his book
Gang Story, in which a man who was no longer associated with gangs but who had been photographed without his consent some years earlier when he was a gang member successfully sued, and Morvan was fined and the book was pulped. So it seems that the decisive consideration may be whether the person photographed has what the courts feel is a legitimate reason to object.