I really don't see what France gets out of this. They are basically throwing themselves on the mercy of the English - it is only a matter of time until the English back stab them and then there is very little that can be done. Besides France would risk an English convoy into Brest before the first builds which would be utterly devestating.

it is an insult. the best strategy for france is to get ird of england ASAP

I've seen this been used very effectively in the mid game on this site. Twice by the same player. (Who controlled France in both of the games I'm talking about)

This cost me a win in a big game, so I'm against it! ;)

It is more commonly occurs not as an intentional thing in the 01-02 period but as a result of a realignment after England moves to the Channel.
For example the following sequence
F Lon-Eng F Lvp-Yor F EDI-Nth
F Bre-Mid, A Mar-Spa, A Par-Bur
Then in the fall the French go to Spa/Por/Bel (or Munich!)
and the English go to Brest and Norway
The French still build two and the English build two.
England cannot hold Brest so it is agreed that England moves out to the Channel and they both attack Germany. Eventually France takes back Brest in the 04-6 period as the English pick up gains in the North.