Exactly one year later he became Emperor taking the title Napoleon III. Leaders in various field were required to swear allegiance and Arago held two such positions, as Director of the Observatory and as secretary of the Academy of Sciences . Arago, a staunch republican, refused to swear allegiance.
Eksaktong isang taon mamaya siya ay naging emperador dinadala ang pamagat Napoleon III. Lider sa iba't-ibang mga larangan ay kinakailangan upang sumumpa katapatan at Arago hawak ng dalawang naturang posisyon, bilang Director ng obserbatoryo at bilang secretary ng Academy of Sciences. Arago, ng isang matatag republikano, tumanggi sa pasumpain katapatan.