This is pure speculation on my part but I'm guessing that President Macron wants to pressure Prime Minister Trudeau into a deal to buy French submarines. The French will probably use their influence leverage within the European Union, to imply that trade with them (EU) and Canada would be lessen. The President will be facing reelection in Apr 2022 and the lost of the Australian submarine contract meant a significant loss in French jobs. Note this is not the first time Canada faced and bent to European pressure due to a trade threat. In 1975, Canada bought
Leopard 1 MBTs after Prime Minister Trudeau (father of the current PM) had a discussion with West German Chancellor Helmut Schmidt. The suggestion was that if Canada wanted trade with Europe, it would have to help defend Europe. A new submarine deal would greatly help President Macron's chances for re-election.
I don't know much about the The Barracuda class (or
Suffren class) except that the Australians were to buy a conventional power variant of this class and presumably this is what the French will offer.
I know that PM Trudeau and his advisors are not politically astute in comparison to PM Harper or Chretien, but I think that they can link loss of trade equals loss of revenue for Canada.