The holding company of Belgian billionaire Albert Frere and Paul Desmarais has raised its stake in Lafarge to just over 20 per cent, France’s AMF stock market regulator said on Wednesday. 
 
The AMF said in a regulatory filing that the  Groupe Bruxelles Lambert holding company now had 20.04 per cent of Lafarge’s share capital, up from a previous stake of just over 18 per cent.