My company hires new grads around 50k and I guess decent startups who make people relocate across continents should pay at least 45k.
I hope you're not saying "low pay" because you compare to the USA. The Europe and the USA are not in the same league, they shouldnt be compared.
I'd say you need be be at least Manager/Director/VP of engineering, depending on the size of the company.
Also by paying less than blue card limit, the devs are basically tied to VisualMeta. Most of the devs don't know German system well and thus are being taken advantage of.
See here for discussion about French salaries.
http://www.developpez.net/forums/f597/emploi-etudes-informat...
That's the main french forum for professional developers tips & tricks & career advice & salaries.
Feel free to open a topic in the aforementioned forum, they'll know better .
To give you a frame of reference, I was pretty well paid in Perpignan after a few years in a company (a bit north of 40k€). The junior devs I hired got south of 24k€.
For a dev job around Paris, it is very low.