Berlin wages are really low in my experience. After taxes maybe 2000-3000 euros per month.
And it was ok-ish safe (in 2013, not sure about now)
Bring on top of that the Germany tax rates and you will quickly be taking less home than in say the UK.
Rents are also not as low as it previously was. It has steadily been rising and buying a place is also out of the question now given how the property market has performed in Berlin.
Don't get me wrong, I love Germany and have personal connections to it but one needs to take everything into account when you make a move to a new city.
But for most people, those that are relocating for a job, healthcare doesn't cost much.
Beside that healthcare is almost free. You may need to pay for some "comfort medicine" (view by the state me or less randomly) and you pay 1€ per visit to a doctor.
The serious stuff is free (actually the more serious, the more free), dental is covered by the outer insurance (the debs depends on your contact), same for glasses.
So France is good when it comes to serious illnesses, gets expensive when having children (plenty of non reinbursed sprays for nose and throat) or when you have serious dental work, especially implants.