Have heard this before, and just found at least this piece (found nothing else like a newspaper clipping, nothing on the Mavic site either):
https://fr.wikipedia.org/wiki/Mavic
".....As for the AVA brand, it disappeared around 1981. Ironically, Rigida was in turn bought by another wheel manufacturer, Wolber, which was itself sold in 1994, for a symbolic franc, to Mavic."
I assume then Michelin sold it to Mavic in 1994, perhaps with a deal to take some staff, property rights, and/or rim manufacturing assets and then Mavic promptly killed off the brand to give more space in the market for themselves.
Rigida a whole other story ... bought in 1989 (sold from Wolber?)
https://www.ryde.nl/homepage/history/
According to Le Parisien newspaper clippings, the Rigida plant in Noyon, France had in the peak +500 employers and at the time of collapse around 2010 only 38 employers.
Really liked the Rigida rims; found the 26" Laser very strong, hardwearing with a very generous brake track.