Bonjour Togaboy
I had the same request on the spanish forum, a couple of months ago. Unfortunately, nobody could help me to trace my friend in spain. I decided to take another approach to the problem.
Since I met my spanish mate in USA (he was my instructor ) I searched his name through the FAA Pilot registry ;
try here ; this provided me with his home adress in spain, I jumped to
this phone book and was able to get in touch with him the same hour .... I don't even talk about the party in Madrid the following evening
If your friend has an FAA Licence, it's highly possible you'll find him. If not, try a search with the second link around major airport in France or Switzerland.
Good Luck & Keep us informed.