According to the SUD-Rail union, SNCF asked Itiremia to put three porters at the disposal of the Israeli delegation when Peres arrived at the Gare du Nord station on March 8th from Brussels, but the firm deliberately sidelined Muslim employees.

"The previous evening, the site manager launched into a strange 'operation' within the workforce, excluding 'blacks and Arabs' because there must not be 'Muslim employees greeting the Israeli head of state!", the union said in a statement.

Questioned by outraged workers, the manager said the measure was taken for "security reasons", the union said, adding that he had acted under orders from the SNCF.

But the railway giant on Monday denied the allegations, saying it had received no requests from Peres's entourage nor from the French foreign ministry to assist with the Israeli delegation.

It did not "give out such orders to its contractor for baggage handlers, the firm Itiremia", the SNCF told AFP.

According to SUD, officials at a committee that monitors working conditions at Itiremia called a special meeting over the alleged incident, after which the internal probe was launched.

"The director general of the subsidiary said the choice (of porters) was made according to the appearance of employees," Bruno Vergerolle, a union representative on thecommittee, told AFP.

"He told us that it was a precautionary measure to avoid employees having to endure humiliation from the protection services of high-ranking people and the diplomatic corps," he said.

Peres called in on his French counterpart Francois Hollande on March 8th after a trip to Brussels where he urged the EU to brand Hezbollah a terrorist group.