Fly-half Frederic Michalak said Samoa gave France the biggest test of their autumn series.
Les Bleus completed a November treble by beating the Samoans 22-14 in a bruising battle at the Stade de France.
On paper Samoa looked the easiest match, but France easily saw off Australia and Argentina, and were behind in the second half against the ferocious south sea islanders.
But Michalak kept his head to kick the hosts to a victory which consolidates fourth place in the IRB rankings ahead of the 2015 World Cup draw.
Samoa's power troubled France throughout the match with David Lemi and Joe Tekori scoring tries, both of which were converted by Tusi Pisi.
"We knew it would be hard, they shook us pretty hard and dominated in the scrum and on the line-outs," Michalak told French TV channel France 2.
"They are quite unpredictable but we knew they'd crack towards the end."
Coach Phillipe Saint-Andre added: "Mission accomplished. We had the objective of winning three matches and we have done it. It was a victory for courage and unity."
France captain Pascal Pape said: "We don't panic anymore, we have confidence in our own strength. We like to suffer together."