The Untold Spy Story of WWI
These plans bubbled below the surface for many years. There were people in both Germany and France who saw a united Europe as the way forward, the way to neutralize Britain.
They finally got the covert backing of Emperor Wilhelm, and France was approached with a proposal to form an Alliance that would be the basis of a united Europe, excluding Britain.
Indeed that was Napoleon's dream, so it easily captured the imagination of the 'right' people in France.