Moutschen entered the Liège Académie des Beaux-Arts at the age of nine.
He received his diploma in 1917 and entered the Association des Architectes de Liège in 1923.
Moutschen designed a number of projects around Liège characterized by a pragmatic approach and an extreme sobriety of style.
His brother Michel Moutschen (1923–1947) was a war correspondent for the Associated Press, killed by a sniper in Vietnam.
[7] His son Jean Moutschen-Dahmen (1929–2001) was Professor Emeritus of fundamental genetics at the University of Liège.