"The release by Azerbaijan and reparation to Armenia of 8 Armenian detainees is another sign of positive developments following the meeting with @EmmanuelMacron, @azpresident and @NikolPashinyan," wrote Charles Michel on Twitter, Reuters reported.
"The EU supports stability and prosperity in the region," added Michel.
Macron added that France had sent over a plane to pick up the released Armenian prisoners.
"Thanks to our diplomats as well as our soldiers who were mobilized for this operation," wrote Macron on Twitter.
Last October, Azeri troops drove ethnic Armenian forces out of territory they had controlled since the 1990s in and around the Nagorno-Karabakh region, before Russia brokered a ceasefire.
Armenia, Azerbaijan and Russia had subsequently said last November that they had signed a deal to end the military conflict over the Nagorno-Karabakh region after more than a month of bloodshed.