He took evening courses in the Montparnasse Quarter in Paris, and graduated from the School of Arts Dératifs in 1938.  He often visited the atelier of "La Grande Chaumière", and exhibited his first oil painting at the "Salon des Indépendants" in 1939.

Since 1951, Jansem has held exhibitions of his work in France (Paris, Amiens, Nantes, Avignon, Marseille, Nancy, Toulouse, Cannes, Mulhouse, Bayonville, Clermont-Ferrand...) and in other countries (Rome, Palermo, Lausanne, New-York, Chicago, Palm-Beach, London, Brussels, Montréal, Tokyo, Osaka, Beirut, Sao Paolo, Johannesburg, Germany, Art Expo New York and Los Angeles.