Parra replaces Maxime Machenaud, who started in France's 33-6 win over Australia and the 39-22 victory against the Pumas.
Thomas Domingo pushes fellow prop Yannick Forestier on to the replacements' bench and hooker Benjamin Kayser takes Dimitri Szarzewki's place.
Fullback Brice Dulin, who was doubtful because of an injury, was named in the starting 15.
"We have decided to trust a good squad for the toughest and trickiest match of the series," Saint Andre said. "We played the first two matches with 23 players."
Saint Andre said that Szarzewski and Machenaud had played "a lot of matches with their clubs".
"I wanted to make some changes. Dimitri understands, he is one of the leaders of the team. He is disappointed but we win and lose with 23 players. The most important thing is the team," the manager explained.
Saint Andre praised Machenaud's performances against Australia and Argentina but said the more experienced Parra also deserved to start.
"Morgan Parra played very well when he came off the bench last week," he said.
With Parra back alongside fly-half Frederic Michalak, the question arose as to who would kick against Samoa at the Stade de France.
"We have two world class kickers who will start the match. Michalak was perfect in the first two games so we will be consistent," said Saint Andre, who added that Parra would probably take kicks from 40 metres or further.
For the first time in three matches, France regard themselves as the favourites.
"We know that the French have problems dealing with that," warned Saint Andre.
Victory is likely to strengthen France's fourth place in the IRB rankings, which will be used for the 2015 World Cup seedings.
France have won their only two matches against Samoa, prevailing 39-22 in 1999 and 43-5 in 2009.
France team: 15-Brice Dulin, Benjamin Fall, 14-Wesley Fofana, 13-Florian Fritz, 12-Maxime Mermoz, 11-Vincent Clerc, 10-Frederic Michalak, 9-Morgan Parra, 8-Louis Picamoles, 7-Fulgence Ouedraogo, 6-Yannick Nyanga, 5-Yoann Maestri, 4-Pascal Pape (captain), 3-Nicolas Mas, 2-Benjamin Kayser, 1-Thomas Domingo.
Replacements: 16-Dimitri Szarzewski, 17-Yannick Forestier, 18-Vincent Debaty, 19-Jocelino Suta, 20-Damien Chouly, 21-Maxime Machenaud, 22-François Trinh-Duc, 23-Yoann Huget.