There's been a lot of immigration until at least the 70s from Spain in Portugal - in fact, the time it stopped is certainly around their entry into the EU (suggesting that making Turkey join the EU is the best way to stop immigration from there...).

I have strong anectodal evidence of Spanish immigration - and integration - my very own concierge is Spanish; her two kids are now in University (in Spain, after going to school here in Paris); some old friends of my wife are the daughter of Spanish laborers in Switzerland and went to univiersity in London and are now working in good jobs in Switzerland.

INSEE shows that Portugal is still the first country of origin of immigrants in France today, before Algeria and Morocco.

In the long run, we're all dead. John Maynard Keynes