Lorelei

Lorelai is the Czech and Slovak form.
Nicknames: Lori, Lora, Lorel(a), Lorelee.

This is not used as, nor is it considered to be, a first name in Germany.

Camilla is wrong. It has been used in Germany, albeit rare, it has recently become more prevalent.

Marilyn Monroe's character's name in "Gentlemen Prefer Blondes" was "Lorelei Lee" which explains the name's popularity in the Fifties. The name's popularity now can perhaps be accounted for by Lauren Graham's character "Lorelai" on "Gilmore Girls," and the popularity of names reflecting ethnicity and mythology, as well as mermaids like "Ariel" in Walt Disney's "The Little Mermaid."