Henry, 31, will return to England after five years playing in France, firstly for Pau in the southwest before he joined the Parisians three years ago.
Apart from one season with Leicester Tigers, Henry has spent his entire career in France, initially in the lower divisions for Rouen and then Nevers.
He is the latest signing for the ambitious energy drink-backed outfit.
Newcastle have already agreed moves for New Zealand back-rower Hoskins Sotutu, Argentina lock Franco Molina and Fiji winger Joji Nasova for next season.
"I've had some inspiring conversations with the club and I can't wait to be part of such an ambitious project," playmaker Henry said.
"I've loved every minute of my time in France and am eternally grateful for how it's shaped me, both on and off the field," he added.
Newcastle are five points adrift at the bottom of the Prem with eight rounds of the regular season to play.
Red Bull took over the lowly northeastern club last August.