France’s state rail operator, SNCF, has pledged to open its wartime archives to the state of California to prove it has “nothing to hide” over transporting French Jews to Nazi death camps.

The pledge came a week after California passed legislation making full disclosure on involvement in taking people to work, concentration, prisoner of war, or extermination camps between January 1942 and December 1944 a requirement for bidding to build a high-speed railway in the state.

Under the Holocaust Survivor Responsibility Act details of any reparations paid must also be disclosed....