What is the defining similarity of French philosophers?

When I think of French philosophers I think of Lacan, Foucault and Derrida. I have not read any of them in depth, but I am interested in doing so. But first, how am I to approach reading them? I can’t help but feel like they are all connected somehow by a common thread. Is that true?<br><br>Let me give some background: I am a chemist who is very interested in philosophy, but I have come to philosophical study by myself and not through formal education. I have read in depth: Mill, Marx, Nietzsche, Russell, Camus and Sartre. I have also read bits and pieces from many other philosophers. I kind of feel like I am missing the commonality between the French philosophers. <br><br>I feel like I could read Lacan, Foucault, and Derrida on my own, but it would be more beneficial if I had a framework for understanding them. Do you believe there is a common thread through French thinkers? I also do not have the time to read all of everything they wrote, so what should I read?<br><br>EDIT: Wow thank you for all your responses. I am going to do my best to go through all of them and keep up with the comments. But keep them coming and I'll try to address them up to the point where I am at in the comments.