For those of us who are still learning.

I'll start.

Thierry Mugler - Tea-eh-(r)ee Moog-la(h)ir OR Mooglur OR Moog-lay, see other thread.

Hanae Mori - On-a (like dancing on-a treetop) Mohr-ee.

L'Occitane - Lox-uh-tahn

Guerlain - Gehr-lahn or Gehr-lehn or Guhr-len

Maitre Parfumeur et Gantier - this is a tricky one.
Maitre: May-t(re)
Parfumeur: Par-fume-err (or par-fume-euhr)
et: a (like the letter)
Gantier: Gahn-tea-ehr or Gahn-tea-a (again, a like the letter).