Judging by the staggering number of Italian and French restaurants in Japan it would be hard to call which European cuisine is more popular: perhaps both, equally.
But this cuts both ways. In the West, Asian restaurants are on every corner. Even in the lowly city where I come from in Ireland, on my last trip home I noticed a Chinese place, which had been around forever, had turned Japanese — the staff hadn't.
It's become a custom of mine to ask the chef or master at these establishments if they have been to the respective country of whose food they spend their days making, and the answer is nearly always no.