I didn't say it stopped, that wasn't the point, immigration has lowered, and it's correlated to the country's need, particularly in workforce. Since France has a lot more younger population than many other European nations it makes sense they don't prioritize more in immigration.

You mentioned immigration isn't an on/off switch, the perfect counter example is Germany in 2016, one country can decide to suddenly 'switch on' and allow 1M immigrants to come to replace their aging population.

As for attractivity, France is actually pretty much well ranked usually, for example the average net income is comparatively superior to the Dutch one, Paris metropolitan area alone has close to the same GDP as the Netherlands despite having 5M population less. That's definitely not a problem of jobs nor lower wages, as for language barrier, current immigration to Europe is for a great part from french speaking countries, English is less used than in Nordic European countries but still widely used and understood. So the barrier wouldn't count that much, France tops both FDI and university/research rankings.