Though it is a beautiful name, Brigitte is severely dated in France. It's popularity skyrocketed in the 1950's, reached a peak in the 60's, and died down by the 70's. It was the 40th most common name given to girls born in the 20th century.
In addition to what bonjour_mon_joli said, Brigitte ranked at #7 in 1955 and #5 (behind Catherine, Sylvie, Marie and Christine) in 1960. He also ranked at #5 in Germany in 1945 (behind Renate, Monika, Karin and Ursula), and #1 in 1950.