He entombed himself in a body-shaped slot carved in a limestone boulder on Feb 22 at Paris' Palais de Tokyo contemporary art museum.
Poincheval, 44, ate stewed fruit and purees while breathing through an air vent. He had some personal items such as a log book and an emergency phone line.
"I'm a little dazed, which I imagine is totally normal after one week living in a rock (...) which hosted me well. I thank it very much for having been so enthusiastic about welcoming me," he told reporters minutes after his release.
"Yes, there were very long moments of loss of self, where suddenly (...) you no longer know where you are, but you are there, and that is what was great (about it)," he said.
In 2014, Poincheval spent 13 days living inside a hollowed-out bear sculpture, eating worms and beetles to mirror a bear's diet.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)
Get the latest election news, live updates and election schedule for Lok Sabha Elections 2019 on ndtv.com/elections. Like us on Facebook or follow us on Twitter and Instagram for updates from each of the 543 parliamentary seats for the 2019 Indian general elections. Election results will be out on May 23.