French investigators questioned three people on Wednesday as part of a judicial inquiry into the Syrian activities of cement and construction group LafargeHolcim, sources close to the matter said.
French prosecutors launched an investigation in June into Lafarge's operations and its possible "financing of a terrorist enterprise". At issue are allegations about payments that were made to banned groups.
One of the sources said that two of the people questioned on Wednesday were former heads of the company in Syria and the third was a former head of security for Lafarge, which merged with Switzerland's Holcim in 2015.
The head of security still works at the company while the two former Syria directors no longer work for the French group, the sources said.
Lawyers for the three declined to comment when contacted by Reuters. A LafargeHolcim spokesman also declined to comment.
An independent internal inquiry found protection payments made to intermediaries to keep open the Jalabiya plant in northern Syria were not in line with its policies.
LafargeHolcim CEO Eric Olsen said afterwards in April he would quit after the company admitted it had paid armed groups to keep a factory operating in war-ravaged Syria.
Olsen said at the time that he had not been aware of any wrongdoing and that he hoped his departure would bring back "serenity" to the group.