Although Eurostar are calling it a strike it is a 'mouvement sociale', industrial action short of a full blown strike in our terms.
About half TGV (and Ouigo and Intercités) services are expected to run.
The advice on sncf-connect.com is the same as usual during disruption: check after 1700 on the day before to see whether your train is cancelled (shows as supprimé), if so what else is running. So after 1700 (1600 here) on Friday you know what the plan is.
If cancelled you can change free of charge on any train up to Monday 19/02 or get 100% refund and, this time, a 50% reduction on a new ticket for within a month. If you booked on sncf-connect that is available automatically, if a 3rd party booking site I don't know what happens.
SNCF Connect : Grève SNCF : prévision et information des perturbations de trafic - SNCF Connect - Aide et Informations
www.sncf-connect.com
As it's Paris-Lyon, as soon as SNCF show cancelled you could see if Trenitalia still have space then get a refund from SNCF.
The bad news is that these are not good weekends to be travelling if you need to rebook. In case you don't know, French school holidays are arranged as 3 zones each with a skiing fortnight. Zone C is already away, zone A goes away this weekend. The following weekend is a disaster with zone B going to the Alps as zone C returns. See
Les dates de la rentrée scolaire et des vacances scolaires de Toussaint, Noël, Février, Printemps et des grandes vacances dépendent de la zone (A, B ou C).
www.service-public.fr
Paris-Lyon on the 17th is relatively OK. If returning, the days up to the 26th are mega-peak as Paris is coming back at the same time as the rest of the north is going away. On usual behaviour I would expect another walkout then with a possible payoff to suspend the industrial action until after the holidays.