AVE is the commercial name for high speed services from the Spanish Rail Operator (Renfe) while TGV is the same for the French SNCF. International services from Barcelona to Paris, Lyon, Marseille, Toulouse (and intermediate cities) are operated as a join service between Renfe and SNCF, so that's why they are called AVE-TGV. (Like if an International Service Canada-USA would be known as VIA-AMTRAK)
It can be said it is the same product, just AVE-TGV trains are part of an International line, while AVE does not leave Spanish borders.
So, what you probably see is a High Speed Service from Marseille to Madrid, that also stops in Barcelona. In terms of train type, service, time and comfort it is the same.
Ultimate Guides to Spain Railways
Like the rail network in most parts of Europe, traveling by train in Spain is simple, economical and efficient.
You should understand that Spain’s transportation infrastructure is generally quite mature, but did you know that Spain ranks behind China and has the second most high-speed rail in the world? Japan has the title of fastest high-speed rail, but Spain's high-speed rail ranks fifth.
Spain is a relatively small country, which means you can easily, cheaply and quickly see more of Spain. All train travel in Spain goes through Renfe-Spain’s nationalized railway network (Red Nacional de F'errocarriles Espafioles), which operates regular city-to-city, inner-city regional train ...
