As mentioned above, currently there are no major interruptions on the TGV network. But note that this is the season for épisodes méditerranéens, which dump a ton of rain in the south and south-east. And overall the country has gotten a lot of rain since last winter (except in the Roussillionn where they need it) so it doesn't take much to cause issues. So keep a eye on the prévisions météorologiques.