Lucian

Also Romansh:
Source: "Vornamen in der Schweiz. Prénoms en Suisse. I nomi in Svizzera. Prenoms in Svizra" (1993) published by the Association of Swiss registrars
https://sursassiala.ch/2015/01/15/familienforschung/

Also Gascon, Provençal and Languedocian: https://ieo-oc.org/spip.php?page=article&id_article=290 --- Source: Institut d'Estudis Occitans

Also Provençal: https://fr.wikipedia.org/wiki/Liste_des_pr%C3%A9noms_occitans (Source: Institut d'études occitanes)
https://oc.wikipedia.org/wiki/Lucian_Duc