PARIS- French investigators held for questioning on Wednesday three former bosses of Swiss-French cement maker LafargeHolcim LHN.S as part of an inquiry into the group's activities in Syria, a judicial source in Paris said.

Prosecutors launched an investigation in June into the company's operations and its possible "financing of a terrorist enterprise". The inquiry relates to allegations that payments were made to banned groups.

One of the three, Bruno Lafont, was chief executive of French company Lafarge before its merger with Swiss Holcim in 2015, after which he became co-Chairman of LafargeHolcim. Eric Olsen was chief executive of the merged company until April this year. The third executive, Christian Herrault, is a former senior executive of Lafarge.

A LafargeHolcim spokesman said the company was cooperating with the French authorities and that there was no indication the allegations against the executives would have an adverse financial impact on the group.

Lawyers for the three men could not immediately be reached.

The questioning of the three comes after a French judge placed three other former Lafarge staff under formal investigation last week, bringing them a step closer to a possible trial.

An independent internal inquiry found that protection payments made to intermediaries to keep open the Jalabiya plant in northern Syria were not in line with its policies.

In an interview published in the French newspaper Le Figaro on Sunday, LafargeHolcim's Chairman Beat Hass reiterated that the company had made unacceptable errors in Syria and that it was cooperating with French investigators.

Olsen quit as CEO in April after the company admitted it had paid armed groups to keep a factory operating in Syria.

(Reporting by Emmanuel Jarry in Paris and Oliver Hirt and John Revill in Zurich; Writing by Ingrid Melander; Editing by Richard Lough and Edmund Blair) ((ingrid.melander@thomsonreuters.com; +33149495518; Reuters Messaging: ingrid.melander.reuters.com@reuters.net))