The Latvian 25-year-old looked in deep trouble as he trailed 6-3 4-1 but he rallied and went on to rack up a string of games which went unanswered by his opponent, who could only pick up five points throughout the entire third set as Gulbis registered a 3-6 6-4 6-0 victory.
The win sealed Gulbis' fourth ATP World Tour title of his career and his second of the current season.
Gulbis was delighted to seal another tour title but is aiming to play at his best on a more regular basis to boost his ranking.
"I feel great, it's my second title of the season - the fourth one of the my career," he told atpworldtour.com
"I made my short term goals. I'm going to be seeded in Melbourne with these points, so that's done. Now everything that comes, comes. I have nothing to defend so it's all good.
"The main key why I'm not yet a top player is the consistency. Everybody knows I can play well for a tournament or a match and then I go downhill. I just need to bring this consistency to bigger tournaments, especially grand slams."
Garcia-Lopez was magnanimous in defeat and was pleased with his level of performance throughout the week in Metz.
"Despite losing, I played some unbelievable tennis all week, so I have to be happy overall," he said.
"Congratulations to Ernests, he deserved the title."