It's unclear what sparked the attack, which left two of the tourists with facial injuries and one with a possible eye injury.
The women were waiting to board a train to Paris at Marseille's Saint Charles station. All four women are in their early twenties. She said all four of the tourists, who are in their 20s, have been hospitalized, two of them for shock.
The acid was thought to be in a spray canister sold in DIY shops for cleaning purposes.
The attack is not thought to be terror-related.
According to reports, a 41-year-old man was arrested by police and the two tourists were taken to hospital.
Fourteen firefighters arrived to the station four emergency vehicles after the incident at 11am.