French battlecruisers after the fall of France

How dangerous would the French Navy be after the fall of France if its older capital ships had been built as battlecruisers?

Very dangerous in economic warfare, because fast battlecruisers could conduct surface raids against British trade.

This follow-up shifts the earlier French design counterfactual into the crisis created by France's defeat. Battlecruisers built for speed and imperial trade protection would become dangerous commerce raiders if captured or employed against Britain. Their ability to move into the Atlantic and choose engagements matters more here than their weakness in a Mediterranean battle line. The answer is concise, but it shows how the same design can become more or less valuable when ownership and mission change.