FYI: that day is WEDnesday and the day before a christian holiday on 26/5=means long weekend to come for many= high demand to go by train-and even more by car making endless ques on the motorway. 10 days later its another such holiday, but on MO=also long weekend (though in FR

You did not clearly mention what train, I guess TGV=fast. THEse trains have quota (quite small) for passholders for 10€/extra, if taken (but somehow I guess on such busy days they have quota=0) as long there are seats its 20€. BUT the app will not show these and tell you ´full´. So best friend rian has posted here many, many times to call SNCF on their /en/ nr or b-rail. OR if you are in FR already now-via a machine.

BUT if you have a little more time and B smart: use the local=regional trains without any need te REServe. Takes longer, but no worries. And they bring you into the centre proper, not in some godforlorn way out in the sugarbeet fields stop on the motorway.

Which train do you want to book?

There is still plenty of availability. Only in the evening, it is starting to become full:

There are also reservation-free options (2 direct ones):

Thank you for the replies, I'll arrive in the airport at night, so I would need to get the trains after 8pm, but I'll try to call to sncf, what do you mean by "call SNCF on their /en/ nr or b-rail", do they have an english menu?