A Rozière Balloon is a special balloon-airship hybrid found on several locations on the map: Istanbul to Beirut, Baghdad to Tehran, and Port-au-Prince to Washington. There is also a similar airship from Brisbane to Auckland, but it is not considered a Roziére Balloon, instead just a plain Hot-Air Balloon.
The Roziére Balloon from Istanbul is only accessible after Passepartout meets a young medical student hoping the flee to political instability of the city. Bewitched by Passepartout (who is still wearing Harem Silks from a misadventure the night before) he does not charge for the journey.
However, if Passepartout has acquired a real Preparation of Paraffin from the Artificer of Bucharest, any of the three Roziére Balloon routes may be sped up so that the journey will take only a single day.