Back during the height of the cold war, there were extensive listening networks in the oceans owned by the US and Soviets that were capable of localizing unique sound signatures with a pretty high degree of accuracy. As I recall, the wreckage of the USS Scorpion was found in this manner.
In the post cold war era, I have no guess if any of these networks are still operating and able to yield usable data. I would hope that the French government has at least asked for a tip off where to look. This kind of information would not be disclosed without approvals at very high levels, and it may no longer be available due to cost cutting measures.