Mousse v Commission nationale de l'informatique et des libertés (CNIL) and SNCF Connect

Holding (summary, not the official text)

Making customers state a title (Mr or Ms) to buy a train ticket is not necessary for the contract and cannot rest on legitimate interest where customers were not told of that interest, the data are not strictly necessary, or the risk of discrimination outweighs it; the right to object does not change the necessity test.