The match was the opener of a Group 5 doubleheader, capped by host St. Kitts & Nevis' 2-0 win over Anguilla.
Hughton Hector and Jamal Gay scored nine minutes apart to put Trinidad ahead 2-1 by the 35th minute, and Keon Daniel and Willis Plaza added second-half goals to complete the victory.
Trinidad, however, finished the match without manager Hudson Charles, who was ejected in the 87th minute for insulting Cuban referee Marcos Brea.
The game marked French Guyana's return to the Caribbean Cup for the first time since 2005, when it advanced within one step of the finals. It started quickly, taking the lead in the 16th minute with a goal by Duncan Darcheuolle.
In the nightcap, Romaine Sawyers and Atiba Harris tallied in the 15th and 20th minutes to pace St. Kitts, which has advanced past the first round in five of the past six tournaments including 2001 when it reached the finals.
It was the first time in six games in over a year that St. Kitts has scored more than a goal in a game, dating back to a 4-2 win over St. Lucia in World Cup qualifying.
The group will continue with matches on Friday, when Anguilla will face Trinidad, and St. Kitts faces French Guyana. The group winner will advance to the second round to face Cuba, Suriname and the runner-up from Group 2.
The second-place team also can advance, but must finish better than Group 4 runner-up Barbados, which had six points and a goal difference of plus-1.