You can now be fined for going over the luggage limit on French trains

Starting from mid-September, passengers now face a €50 fine for exceeding the luggage allowance.

France has introduced new rules regarding luggage on trains with fines for travellers who don’t comply. 
Limits on the number and size of suitcases will become obligatory on France’s high-speed services in mid September.
Earlier this year, Italian operator Trenitalia also proposed stricter regulations on luggage that would have limited passengers to two items per person. 
However, the proposal was contested by consumer rights groups and was withdrawn.  
In February, French national operator SNCF announced new limits for the amount and size of luggage on high speed TGV InOui and Intercité trains.  
Passengers are now limited to two large pieces of baggage measuring a maximum of 70cm x 90cm x 50cm per person plus a smaller item like a backpack or laptop case with dimensions of up to 40cm x 30cm x 15cm.
Passengers are also allowed to carry a handbag or purse. Items including pushchairs and buggies, sports equipment and musical instruments do not count towards the luggage limit.
The new regulations came into force on 15 February but without fines for noncompliance. Starting from 15 September, passengers now face a €50 fine for exceeding the allowance. 
Those travelling on the TGV budget OuiGo services are already subjected to baggage regulations. 
Passengers holding a standard ticket are permitted one piece of luggage measuring up to 36cm x 27cm x 15cm and one piece no bigger than 55cm x 35cm x 25cm. 
Passengers can pay an extra charge to bring additional items. 
Local TER trains don’t impose a luggage limit but storage space can be limited and passengers must ensure baggage is stowed safely and does not become a hazard for other travellers. 
Standard and Standard Premier ticket holders on the Eurostar travelling between London and Paris are permitted two items of baggage and one handbag. 
There are no weight restrictions but passengers must be able to carry and lift their suitcases without requiring assistance.