In 1828 Lesseps was sent as an assistant vice-consul to Tunis, where his father was consul-general. He aided the escape of Youssouff, pursued by the soldiers of the Bey, of whom he was one of the officers, for violation of the seraglio law. Youssouff acknowledged this protection given by a Frenchman by distinguishing himself in the ranks of the French army at the time of the French conquest of Algeria. Lesseps was also entrusted by his father with missions to Marshal Count Bertrand Clausel, general-in-chief of the army of occupation in Algeria. The marshal wrote to Mathieu de Lesseps on 18 December 1830: "I have had the pleasure of meeting your son, who gives promise of sustaining with great credit the name he bears."