Marcel Sangenez was the 7th Marquis de Sangenez. He was the leader of a French resistance group during World War II.
He rescued Professor Pierre Vedrun, his daughter and the Third Doctor from their German captors. He suspected the Doctor of working with the Germans and planned to have him shot until Monique found proof he was telling the truth about being from the future.
Together, they modified Vedrun's time travel device to defeat Kapitan Ernst Wolfgang Spiegal's plans. (TVA: Timebenders)