NEW : At least six people were killed in the accident , France 's president says . Carrying about 370 people , the train was passing through the Bretigny-sur-Orge station . Comment: France 's national railways company says the derailment was an accident . The cause of the derailment is being investigated , minister says .
NEW : At least six people were killed in the accident , France 's president says . Comment: France 's national railways company says the derailment was an accident . The cause of the derailment is being investigated , minister says .