Prior to joining JCDecaux, France had roles as the UK group managing director of rival Clear Channel and as sales director of Express Newspapers.
France said: "After over 20 years working in the media industry, it feels like the right time to take a break and to think about the next stage of my life and career."
Sullivan assumes the role of managing director of the division that holds contracts for the likes of Heathrow Airport, Eurostar and St Pancras International.
He will report to Jean-François Decaux, who said: "Alan's understanding of the media landscape and established relationships with our airport media partners will be invaluable in his new role.
"As the launch of Heathrow Terminal 5 and the London Olympics demonstrated, airports provide an increasingly important platform for clients and their brands to reach influential, global audiences."
JCDecaux's Airport division operates as a standalone division of JCDecaux, which enjoyed acclaim five years ago when Terminal 5 at Heathrow opened with digital screens integrated within the core of its architecture.