I lived for 6 years in Remscheid, Germany, the city with the highest percentage of Muslims of any (mostly Turkish.)  I was told the official figure was around 22%, very significant, out of a total population of some 120,000.

Except for very isolated instances, I never saw any kind of trouble.  in fact, when Germany played Turkey in the EM semis, there was a kind of joyous rivalry which spilled onto the streets.  My impression of the entire time there was that integration was proceeding quite well.

This is not to say there weren't people who were extremely prejudiced, merely that social integration was gradually working.

Even among the older women there were some who did not dress according to Muslim tradition, as well as young girls who did.  On the surface at least, all were accepted.

Personally, i had a very positive experience interacting with a completely different culture.

"Life shrinks or expands in proportion to one's courage." - Anaïs Nin