These are the only references I was able to find:

Dissing H. - 1966: A revision of collections of the genus Helvella L. ex St-Amans emend. Nannf. in the Boudier Herbarium. Rev. Myc. 31: 219:
"Leptopodia corbieri Malençon, Bull. Soc. Myc. Fr. 43: 95, Pl. 6, Fig. 7 (1927) is considered to be a synonym of Helvella stevensii. Unfortunately there is no material left of L. corbieri (MALENÇON, personal information)."

Dissing H. & M. Lange - 1967: Notes on the genus Helvella in North America. Mycologia LIX (2): 355:
"Unfortunately there is no specimen preserved of Leptopodia corbieri Malençon (Malençon, personal communication) but his description agrees so well with Peck's (1904), and with Danish collections of H. stevensii, that we have no doubt that L. corbieri and H. stevensii are identical."

In his monograph Dissing (1966) simply list this name as a synonym of H. stevensii.
The same in Häffner (1987: 155), and it's curious to note that he use H. stevensii in the synonym's list but in the text he prefer H. latispora, with H. stevensii reduced as a synonym. Häffner doesn't write anything else about L. corbieri, but the protologue is cited in the bibliography, so I presume he agrees with Dissing's opinion.
Both these authors use "corbieri" and not "corbierei".

It should be very interesting to see the original description and the plate, I haven't got it; can you make a scan?

Oops, J'ai répondu en anglais...! Je vais traduire si vous voulez... pardon!

Merci beaucoup