He also befriended political exile and fellow French nobleman Charles Maurice de Talleyrand-Périgord, collaborating with him in various business ventures.
[2] Mathurin returned to France in September 1793 and became assistant to Jean Antoine Joseph Fauchet, Minister Plenipotentiary to the United States.
Laforest accompanied Joseph Bonaparte to the Congress of Lunéville as first secretary of the legation, then was sent to Munich, and then to the Diet of Ratisbon as chargé d'affaires extraordinaire.
[1] On 1 May 1805 Mathurin was named Minister Plenipotentiary in Berlin, and undertook his duties with honor during the Austerlitz campaign and the start of the war with Prussia.
[1] On the first Bourbon Restoration Mathurin de Laforêt was appointed interim Minister of Foreign Affairs in the provisional government from 3 April to 12 May 1814.
After the return of Napoleon from Elba during the Hundred Days, on 11 May 1815 he was elected to the Chamber of Representatives for the department of Loir-et-Cher.