Belgian building materials group Etex won European Union approval on Friday to purchase most of Lafarge’s plaster activities in Europe and South America.
Lafarge is selling assets as part of a plan to cut its debt by EUR2bn.
The European Commission, the EU competition watchdog, said the parties were not close competitors and the transaction would not significantly alter the market structure.
While there was some overlap in the production of fire resistant boards, the Commission said this would not have a major impact.
"The boards made and sold by Etex and the Lafarge are based on different materials and display different performance levels in terms of fire-resistance time and their combined market share does not give rise to any competition concerns," the Commission said in a statement.