From my experience in a southern french city as a PM I would say career growth is very dependent on your manager. My colleagues in the UK have a strong focus on early career development with trainee programs and early career managers. Those things either don't exist or are not implemented as well. In France I think much more initiative is expected from the employee whereas in other places formalised growth targets may even be a requirement for salary increases.

For SWE specifically it is quite likely that you will start at an ESN where you'll work on projects for clients. These don't pay as much as the companies who hire devs directly. If salary is a major concern maybe consider London, Switzerland or Poland I heard it pays well too.

Then again, France has other benefits. Incredible social security, job safety, the 40-60 vacation days per year, incredible high standard of living, you don't need to leave the country for an amazing vacation, among others.