The wreckage of a French submarine that mysteriously disappeared with 52 crew members on board in 1968 has been found, ending 51 years of agony for families of missing crew members.

The disappearance of the Minerve submarine from near the port of Toulon, on France’s Mediterranean coast, on January 27, 1968, shocked the French navy.

After decades of speculation about the sub’s fate, it was located by a team of naval vessels and international marine experts on Sunday, about 45 kilometres south of Toulon.

The wreckage was discovered in three parts spread across 300 metres more than two kilometres below the water’s surface.

France’s armed forces minister Florence Parly shared the good news on Monday, describing the discovery as “a success, a relief and a technical feat”.

“I am thinking of the families who have waited a long time for this moment,” Ms Parly tweeted.

Nous venons de retrouver la Minerve. C'est un succès, un soulagement et une prouesse technique. Je pense aux familles qui ont attendu ce moment si longtemps. pic.twitter.com/pjDnj7lEyb

— Florence Parly (@florence_parly) July 22, 2019

At the start of the year, Ms Parly announced a new search mission for the Minerve, in response to pleas from families who wanted to find out what happened to lost loved ones.

She said “recent technological advances in underwater exploration, including the use of new sonars and research drones” had made the new search possible.

Researchers from American exploration company Ocean Infinity also helped to identify the submarine using sea-bottom mapping and data sourced by the French navy.

French navy chief Christophe Prazuck tweeted: “Here lie our 52 missing comrades from January 27, 1968”.

Ici reposent nos 52 camarades disparus le 27 janvier 1968. pic.twitter.com/u194eOep4M

— Chef d'état-major de la Marine (@CEMM_FR) July 22, 2019

To this day, however, no one knows what caused the Minerve to sink.

The Mediterranean’s Maritime Prefecture spokesman Stanislas Gentien told The New York Times: “The most important thing was to locate the Minerve to help families grieve”.

“We won’t try to understand how it sank,” Mr Gentien said.

A ceremony commemorating the lost crew members is expected to be held at sea, above where the wreckage was found, later this year.

Widow Therese Scheirmann-Descamps is among family members of missing sailors on boad the Minerve still looking for answers. Photo: Getty

Herve Fauve, the son of the Minerve’s commander Lieutenant Andre Fauve, described the heartbreaking moment he found out his father was dead in a blog dedicated to the missing submarine.

When two marine officers told his mother the news, Mr Fauve said she turned to him and said directly: “Your father has died. His submarine sank.”

In keeping with naval tradition, the French navy said the wreck will stay where it is and serve as a final resting place for the sailors.