When did banks offer services on Minitel? https://fr.wikipedia.org/wiki/Minitel suggests a demonstration version was available in 1980

> À l'automne 1980, 2 500 foyers volontaires de Versailles, Vélizy-Villacoublay, Jouy-en-Josas, Buc, Bièvres et Les Loges-en-Josas reçoivent un terminal Vidéotex. Du côté des services, près de 200 fournisseurs participent à l'expérience, se donnant ainsi l'occasion de tester ce nouveau moyen de communication auprès du public. Les services remportant la plus large adhésion seront les annuaires téléphoniques pages blanches et pages jaunes (services gratuits), la presse, la vente par correspondance, la SNCF, les banques ainsi que la messagerie.

but https://www.bbc.com/news/magazine-18610692 says commercial roll-out wasn't until at after 1982:

> Rolled out experimentally in Brittany, Minitel went national in 1982, offering the telephone directory and not much else.

> Gradually the offer increased to a vast array of services - banking, stock prices, weather reports, travel reservations, exam results, university applications, as well as access points to various bits of the state administration.