OK, thanks to @bohwaz for clearing up the SNCF luggage rules
See pages 35 and 178 of SNCF's terms of carriage - PDF https://www.sncf-voyageurs.com/medias-publics/2024-07/tarifs-voyageurs-version-5-juillet-2024-VDEF-FR.pdf
Your luggage needs to VISIBLY indicate your name, and NOTHING ELSE
Note: despite SNCF's own luggage labels having a field for telephone number, this is NOT OBLIGATORY
Also the name being visible would be - for example - covered by you writing the name directly on the bag. It does not have to be a separate label
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