Diocesan Catholic Church:
Make a donation to the Catholic Church by diocese
https://eglise.catholique.fr/denier-eglise/
Catholic Communities:
Make a donation to the Monasteries Foundation, check "I prefer to dedicate my donation to a monastic community" and choose the desired Monastery, for Finistère for example the Carmelite Monastery of Morlaix:
https://don.fondationdesmonasteres.org/soutenir
Make a donation to the Fraternity of Saint Vincent Ferrer
Make a donation to the Convent of the Dominicans of Avrillé
http://www.dominicainsavrille.fr/pour-aider-la-vie-du-couvent/
Make a donation to the Augustinian Sisters Community
https://augustines-malestroit.com/nous-soutenir/faire-un-don-pour-la-communaute/
Catholic Associations:
Make a donation to the Don Bosco France Foundation
https://www.fondationdonbosco.org/articles_fondations/faire-un-don-3/
Make a donation to BICE for the protection of children
https://bice.org/fr/nous-soutenir/faire-un-don/pourquoi-faire-un-don-au-bice/
Make a donation to Secours Catholique (Caritas France)