The six-foot 218-pound Giguere spent the last three season with the Hamilton Tiger-Cats.
"We are very pleased that Samuel has decided to join us in Montreal," said Alouettes general manager Jim Popp. "We are able to add a solid contributor on the field and bring home a Quebec patron. We are excited about the versatility that Samuel brings and look forward in integrating it into our offence."
Last season, the 29-year-old receiver had 520 receiving yards while scoring one touchdown. He averaged 12.7 yards on 41 catches in 16 regular season outings. In his three seasons with the Tiger-Cats, the Sherbrooke, Que., native recorded 1,543 receiving yards and three touchdowns on 116 receptions.
Giguere, selected eighth overall in the 2008 CFL Canadian draft by Hamilton, played his collegiate career with the Sherbrooke University Vert et Or, earning the team's rookie of the year honour in 2005 as well as a nomination on the CIS first-team all-Canadian in 2007.
Before joining the CFL in 2012, Giguere was a member of the Indianapolis Colts for two seasons, suiting up for a game where he returned five kickoffs for 122 yards. He also spent one season on the New York Giants practice squad.