PARIS, June 5 (Reuters) - French police raided the headquarters of national railway operator SNCF as part of an investigation into contracts handed to U.S. computer company IBM , a spokeswoman at the company and a judicial source said on Wednesday.

"It's normal process. Since there is a complaint, investigators do their work," the SNCF spokeswoman said. "We have handed over the documents that were requested."

The raid was carried out on Tuesday, the SNCF spokeswoman added.

The financial prosecutor in 2016 opened an investigation into possible irregularities in the award of contracts almost a decade ago to IBM for computer equipment, a judicial source said.

A representative for IBM's French unit could not immediately comment. (Reporting by Inti Landauro, Caroline Paillez and Emmanuel Jarry; edited by Richard Lough)