The Switzerland international was at the Veltins Arena for one season after transferring from Leverkusen.
However, the 28-year-old will join Armin Veh's side for the remainder of the campaign once he has returned from international duty.
"I'm really delighted that it has worked out and that I've got to know the city and the team," Barnetta told Frankfurt's official website.
"First of all, I've got to play for the national team and I'll come back to Frankfurt in ten days with (Frankfurt and Switzerland team-mate) Pirmin Schwegler."
Barnetta is due to feature for Switzerland in the FIFA World Cup qualifiers against Iceland and Norway on Friday and Tuesday respectively.
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