Tigris is an old friend of Cressida's and Plutarch Heavensbee who lives in the Capitol. She used to be a stylist assigned to work for the tributes of District 1. She was fired during The 66th Hunger Games since President Snow didn't think that she was pretty enough. She is now a shopkeeper selling fur-lined clothes in a small shop in the Capitol.
Since her father was a zoo keeper, he named his children after animals that were there. He obviously named this character Tigris. Tigris took this name to a new level by looking like one.
When Cressida brought Pollox, Katniss, Peeta, and Gale to Tigris' shop, Tigris led the remaining members of Squad 451 to a secret cellar inside her store, which was hidden by a rack of clothes. She cared and fed them while they stayed, and informed them of what was going on in the Capitol. When she went out to spy on the Capitol's current state, she returned to tell the squad that the rebels had moved into the city and caused many residents there to lose their homes. She also told them that the government was forcing shop keepers and safer residents to provide refuge. This is what drove Squad 451 out of Tigris' shop after she redesigned their looks to make them appear as Capitol citizens. After they left, Tigris housed many refugees kindly and survived on after President Snow was over-thrown.