Used sometimes as spice, but that's not traditional. Called ruzmarin, which is just the local variation of the same word.
The traditional use is for weddings. Every svat (member of the wedding party, i.e. guest or host) wears one pinned on the lapel. The pinning is done by two teenage girls, and is paid some symbolic sum by everybody (and the girls should keep the money). For most people, the smell of rosemary is a reminder of weddings in general.
Recently it seems to be hard to come by a decent amount of rosemary branches, or the florists are charging too much for it, so cheap Chinese fake flower(like gadget)s are used instead. No fragrance at all.