He studied at the École des Beaux-Arts de Paris in the studio of Louis-Jules André, then in 1890 in that of Victor Laloux.
Gaining his diploma in 1891, in 1892 he won the Deuxième Second Grand Prix de Rome with his design entitled "Un musée d'artillerie".
Head architect of civil buildings and national palaces, in 1929 Tronchet was entrusted with the construction (in only 8 months) of a new building for the ministry of employment on place de Fontenoy in the 7th arrondissement of Paris by the minister of employment Louis Loucheur.
He used the most modern materials and techniques and famous decorative artists, such as frères Martel for the sculpture and Jacques Grüber for the glass windows.
His memory is perpetuated today by a foundation and, during the annual ceremony of the Académie des Beaux-Arts under the coupole of the Institut de France, this awards a prize to encourage a young artist (usually an architect).