In September I got a (permanent) junior faculty position in France. The academic year is about to finish and I am taking stock of the year to see if that is really the right place for me to be. Before moving onto this position, I was doing a postdoc in the US and confess that I accepted this position in France mostly because was permanent. Now, if I look back over the year, the main thing I did not enjoy was the teaching load I was given, it was absolutely unsuitable for someone that is starting as a junior professor, but this is the way it is in France and it is not going to get any better. So I was thinking whether I should try to look for other opportunities back in the US and wondered perhaps someone with a wider view could provide me with some tips on that.
I lived through this same situation myself: I had only really known the US system when I accepted a MCF position in France, and was pretty overwhelmed during my first years. For example, my first year I had to prepare several cours magistraux, and I didn't know enough to refuse. At one point I explored returning to the US, in fact for two years I moved back to Boston, but in the end I found a better return on investment making the French system work for me.
Here are some take-aways.
If you are ambitious and your research record is good then you should very seriously consider applying for a position as research scientist at a national institute: CNRS, INRA, Inria, Inserm provide working conditions superior to the best research universities. You can still teach undergraduates if you want to.
In my case I went MCF to DR, but MCF to CR is more typical.
Faculty in the US have a lot of administrative responsibilities and committee work that aren't counted towards their teaching load. In most French schools you will get a décharge from your service for this work and you can negotiate that. In the end of my time as an MCF some 40% of my service de 192 was counted this way.
Taking on Masters students early is important for getting ahead, and while the hours counted towards your service don't completely represent the work that is involved, they can be far more rewarding. Especially if you have ambitions.
As a tenured French civil servant you are free from the precariousness that junior faculty face in the US.
In France, advancement is almost entirely based on research output; taking on administrative responsibilities is a necessary evil but will not in itself get you promoted. Don't get suckered into responsibilities early; do enough to show you are a team player but try to save your non-teaching time for research projects.
The US research system is very individualistic, in my experience junior and senior faculty are pretty much expected to go it alone, and hire students to work with. The French system is very team oriented and perhaps half of a team's members will be permanent faculty or staff. Find a good team.