The Isle Of Love (1922) aka An Adventuress aka Over the Rhine (1920)
As the government of Alpania, a seaside European republic, is threatened by revolutionary monarchists, three American adventurers--Jack Perry, Dick Sayre, and Lyn Brook--arrive in the country and immediately become embroiled in the civil strife. Perry offends the monarchists, who capture him and sentence him to death before a firing squad. Brook rescues his compatriot by bombing the complex, thus killing Perry's captors. Disguised as a woman, Perry infiltrates the royalists' circle where as "Fedora" he quickly becomes a court favorite and earns the love of Zana, an Alpanian woman. While Perry carries news of the monarchists' plot to the republicans, Brook, donning feminine attire and calling himself "Thelma," diverts Grand Duke Nebo. Perry is recaptured, but commandeers an enemy airplane to safety. After an automobile chase, Perry eludes the revolutionaries and escapes to America with Zana.
https://www.imdb.com/title/tt0135475/?ref_=nm_flmg_t_21_act
https://www.imdb.com/title/tt0135475/?ref_=nm_flmg_t_21_act