original: Berlin and Paris developed thriving émigré communities.
simplifications: Berlin and Paris grew thriving émigré communities. Berlin and Paris created successful émigré communities. Berlin and Paris built thriving communities. Berlin and Paris developed thriving immigrant communities. Berlin and Paris developed strong émigré communities. Berlin and Paris got thriving émigré communities. Berlin and Paris developed thriving communities of immigrants. Berlin and Paris developed thriving communities of people who left their own country for political reasons. Berlin and Paris developed thriving immigrant communities. Berlin and Paris have evolved a thriving immigrant community.