SNCF's cut-price Ouigo TGV, which emulates low-cost airlines, will be extended to other routes from next year.
The move is expected to include services at Paris Charles de Gaulle airport, which has its own mainline station, and there are reports Ouigo may also run to Strasbourg in the years ahead.
If this happens, it would mark an important development as Ouigo's initial service was planned for the original high-capacity TGV route linking Paris with south France.
However, SNCF is also taking a leaf out of the airlines' book and will squeeze more passengers onto its TGVs as a way of reducing costs.
No less than 100 more passengers will have to fit onto a Duplex double-deck TGV, meaning the overall seat count will rise from 456 to 556 passengers.
This could be achieved by slimming down first class, but the main increase in passenger numbers will be driven by the adoption of new slimline seating.
And standard class seat space today is hardly generous.
Jon Worth, EU expert and regular rail traveller, said "If you make the seat pitch any smaller in a TGV and you won't be able to open a laptop. Current TGVs are both cramped and make poor use of space."
Other than air transport and private car, SNCF faces little competition within France itself. And passengers cannot fall back on cheaper, but slower, conventional trains because they were axed at the time when TGV lines were opened.
But this situation is set to change radically. France, like Germany a couple of years ago, is set to regulate its long-distance bus services.
SNCF expects to lose Euros 200 million in in revenue, according to La Tribune. The TGVs alone stand to lose earnings of €150 million.
It therefore has no choice but to improve quality and introduce a range of new, more affordable fares.
But why would anyone choose a bus over a TGV? Simply because not everyone needs, or is prepared to pay for, 300 kph train travel, while conventional trains have been withdrawn so as not to compete with TGVs.
German experience shows that travellers are shunning high-speed trains for slower but cheaper buses. And passengers comprise business travellers because some buses are operated by DB itself. It means they ply main routes linking airports to prime city centre locations (see news, December 2014).
Indeed, DB has lost so much traffic to those long-distance buses that it wants to spend millions on improvements to stay competitive.
It is true that SNCF is already a bus operator through iDBUS. But these services operate internationally and, like DB with its IC Bus network, we may well see SNCF operating bus routes in time to come.