Visa to visit the UK for Russian wife of a British citizen (French resident)

Yes, you should be able to visit the UK together without visa, at least if your wife has an article 10 residence card, which would usually be the case in this situation (in French, this is called a carte de séjour mention membre de la famille d'un citoyen de l'Union).

I too am a British citizen living in France with my Russian wife who has a Carte de Séjour. Have a look at the following link.

https://www.gov.uk/government/publications/entering-the-uk-as-the-holder-of-an-article-10-residence-card/entering-the-uk-as-the-holder-of-an-article-10-residence-card

I would recommend writing to or calling UK Visas and Immigration to be sure.