His other brother Baron Paul-Ernest de Cartier (1920-1977) tried to reach England during the war.
This marriage was at the origin of his professional activities within the multinational Eternit, of which the Emsens family is a major shareholder.
He was also active within the publishers and printers company Brepols in Turnhout and its subsidiary Carta Mundi.
During the first decade of the 21st century these firms endured financial problems and parts of it suffered bankruptcy.
On 13 February 2012 Louis de Cartier and Stephan Schmidheiny were both condemned to 16 years imprisonment by the Court of Turin in the Eternit case.
De Cartier died on 21 May 2013 at the age of 91, few days shy from the appeal sentence of the Turin trial.