Verbal forms are attested since at least the early eighties.

Conclusion : lorsque la femme télétravaille à domicile, elle le fait dans la salle à manger…

Pénélope, pour l’histoire des femmes, Collectif, 1982.

It wasn’t mainstream for a while because WFH wasn’t common at all except in niche sectors.

I believe I’ve been using the verb télétravailler since at least 15 years because that was already an option in the companies I worked for.

Because of the pandemic, the verb is now ubiquitous in government and corporate communication, e.g.:

L’employeur peut-il refuser que je télétravaille ?

• Oui, mais il doit motiver sa réponse.