German teams are still bigger (and better) than French teams, what I said about a kid playing in Motpellier wasn't related to him playing at Montpellier, more at which teams and players he plays AGAINST while he's at Montpellier, that's why the doubts about players exist, they're good, but how good are they opponents?.
As for how many people watch a Barcelona vs Malaga outside of Spain, well, you can see it yourself by joining the past season La Liga thread for example, with his 244 pages, and comparing it to the Ligue 1 and 30 pages, you think the 211 page difference is built solely in Real-Barcelona-Atletico matches? That's the exposure of playing in a top league vs a 2nd tier league, and works like that in any other way, that's how La Liga, a Spanish (46M population) competition gets more TV revenue than Ligue 1 (67M and higher GDP per capita), it's because a lot of people from out of Spain watch Real and Barcelona against lesser teams, the same way I'd rather watch a United - Charlton Athletic in the FA cup than a PSG - Nantes.
So yeah, I think that by choosing Ligue 1 as a destination to spend the prime of his career instead of La Liga, Premier League or Bayern/Juve is a step back unless he pulls something magical (with luck required) and wins a CL in 3 years, but even Cristiano Ronaldo had to wait five years to win a UCL title with the biggest club in the world, so excuse me if I'm inclined to believe Neymar has taken a bet with awful odds if his goal is becoming a Legend in European football