It also operated in defence of France 's overseas territories and colonial empire .
The role of the French submarine force in 1939 was to act in concert with the French fleet and with France 's allies against the Axis powers , with particular responsibilities in the Mediterranean .
It also operated in defence of France 's overseas territories and colonial empire .
The role of the French submarine force in 1939 was to act in concert with the French fleet and with France 's allies against the Axis powers , with particular responsibilities in the Mediterranean .