Complex sentence: First formed in the French Air Force, they were rapidly integrated into the French Army, French Navy, National Gendarmerie and from the British Armed Forces, then dispersed in the ensemble forming developing components of the Armed Forces of France.
Split into simpler sentences: First formed in the French Air Force, they were rapidly integrated into the French Army, French Navy, National Gendarmerie and from the British Armed Forces. They were then dispersed in forming the developing components of the Armed Forces of France.