[MMM]

Nobody in that commercial is from an area that speaks Tsugaru-ben.

Riisa Naka is from Nagasaki and I think it is pretty clear she is speaking French. Morisanchu (trio) is not from that area either, so it would be weird for them to use such a dialect.

I think the joke is Riisa Naka is speaking French and the Morisanchu girl wants to look cool by speaking French back, but is speaking Japanese with a bad French accent.