Taking a surfboard on SNCF train in France

I am flying out the Paris next month and planned on taking the sncf train from Bordeaux —> Paris with my 6’6 board bag.

Has anyone had experience taking surfboards on trains in France/Europe before? A friend of mine had no problem but their bag was substantially smaller than mine and I’m worried I won’t be allowed on. Seems as though they technically allow them as long as they’re not bigger than a boogie lol

Any advice would be appreciated. Thanks.