The former West Ham striker will help add depth to the Timbers front line with Bright Dike sidelined with an ACL tear.
Piquionne, 34, brings Premier League experience to Portland, including seasons with Portsmouth (2009-10) and West Ham (2010-11). Prior to moving to the EPL, he played with Saint-Étienne and Lyon in France.
"Frederic made a strong impression during his trial and gives us another quality piece in the striker position,” said Timbers head coach Caleb Porter. “He is a proven professional at a high level and helps our depth with Bright Dike out. We are very pleased about this addition to our club."
Piquionne plays internationally for Martinique, and recently helped the team qualify for the 2013 CONCACAF Gold Cup with a top-four finish in the 2012 Caribbean Cup. He made one appearance in a friendly for France.