…rock, jazz, savoir-vivre, haute couture, pret-a-porter (you are allowed to skip non-Polish diacritics in foreign words)…
EDIT: Anyway, here's a big list of many of the foreign words. Some of them might be pronounced as written, but many don't. Check the entries individually.
As immery wrote, that's "Polish trying to pronounce French". That's just how it was 'implemented' in our language, regardless of the fact that French actually doesn't pronounce it like that. Still, pronouncing it differently would be really strange for most Polish people, I believe.