Just wondering... I'm hoping there are some french natives/speakers on tpf!
If you want to say 'he is a heartbreaker' it's 'il fait des ravages', I thought... A male heartbreaker is a charmeur, bourreau, Don Juan or tombeur, and a female heartbreaker is a ravageuse or séductrice.
Hope it was a bit helpful
I always liked the phrase "La Belle Dame sans merci." from Keats.
Briseur de coeurs or Don Juan...??
Femme fatale -- for the female version