Complex sentence: A minority of the French forces escaped abroad and continued the fight under General de Gaulle (the "Free French" or "Fighting French"), and the French Resistance conducted sabotage operations within German-occupied France.
Split into simpler sentences: A minority of the French forces escaped abroad and continued the fight under General de Gaulle (the "Free French" or "Fighting French"). On the other hand, the French Resistance conducted sabotage operations within German-occupied France.