My experience of France (I have family there) is that they eat real food that has had minimal processing, three sit down meals with no snacking in between. They don't seem to drink soft drinks either. Those croissants may well be healthier because they have huge amounts of real butter in them (can't prove that they are healthy of course). I know that many French people work very hard to keep the weight off though. It is socially unacceptable in many parts of France to be fat and the pressure to stay slim is huge.
Nothing better than a baguette and a hunk of French cheese - yum.