Tran Quoc Tuan, vice president of the Vietnam Football Federation (VFF), said this is part of long-term plans to expose younger talent to regional and international competition.
Players in the U20 squad will represent Vietnam at the SEA Games next year.
VFF also focuses on other younger age groups since there are not many tournaments for them, he said.
The French tournament also provides an opportunity for young players to take part in training camps abroad and helps discover new talent for the future, he said.
The Toulon Tournament, officially the Maurice Revello Tournament, is a prestigious event that brings together players from many strong footballing countries.
Future stars who have played in it include France's Thierry Henry, Portugal's Rui Costa, England's Alan Shearer, Argentina's Javier Mascherano, and Colombia's James Rodriguez.
Vietnam, under French coach Philippe Troussier, will be one of 12 teams from around the world taking part this year. The full list has not been announced yet but DR Congo, England and Japan have confirmed their participation, according to the tournament's official Facebook page.