Found it! The story is told in a 1991 book by Geneviève Carbone (La peur du Loup , Galllimard), an ethnozoologist and apparently an expert on wolves. The only snippet available only though is as follows:

"Plus tard, sous Louis XIV, un stratège proposera à son roi un plan de conquête de l’Angleterre comme suit : «Un loup mange un homme en deux jours, débarquez dix-mille loups Outre-Manche, en quelque temps, il n’y aura plus un seul Anglais. » "

Translation: Later, under Louis XIV, a strategist proposed to his king a plan to conquer England as follows: "A wolf will eat a man within two days, so let loose ten thousands wolves on the other side of the English Channel, and soon there will not be a single Englishman left."

No mention of wool though, or how this strategist planned to both collect 10,000 wolves and ship them to England and disembark them there while preventing these wolves from eating a whole lot of Frenchmen first. Perhaps you can find more detail in the book.

Edit: The story about the wool is told in: Jean-Marc Moriceau, L’homme contre le loup, Une guerre de deux mille ans, Fayard, 2011 (found it through Google books, here). This is the basis for the analysis that English wool is better than the French because the English are able to let their sheep stay outside day and night, which the French can't do due to the presence of the wolves. This analysis is sourced to Jean-Baptiste Colbert, Louis XIV's treasury minister and one of the intellectual founders of mercantilism. The French are jealous but there is no indication that this is the basis for the plan to let loose wolves in England .