A spokeswoman for the festival confirmed the move to phase out the managing director role. However, Cannes Lions was unable to say whether Ascential was planning to create a new role to replace it.
In an internal announcement seen by Campaign, Ascential Events chief executive Philip Thomas said the "difficult decision" was forced by the need to reassess the company's cost base following the £300m sale of its exhibitions business and a "challenging environment".
Thomas, who is also the chairman of Cannes Lions and was its chief executive until 2016, wrote that he would step in to run the festival on a day-to-day basis and thanked Papa for his "unwavering commitment" and "leadership in turbulent times for the festival".
"The decision was incredibly difficult to make and we are genuinely sorry to see him go, as I know you will be. I am grateful for the platform he has now created, because in his own words we ‘have our mojo back’ and the coming year is full of possibilities and opportunities," Thomas said.
The "turbulent times" Thomas refers to reflect belt-tightening in the ad industry and complaints that the festival had lost its focus, sparking a decision by Publicis Groupe to sit out this year and a shortening of the schedule by the organisers.
There was a 21% drop in the number of awards entries this year and industry sources say attendance by leading holding companies dropped by up to a quarter (not including Publicis Groupe).
However, Ascential chief executive Duncan Painter has claimed that attendance by marketers is showing at least double-digit growth.
Papa’s departure follows that of Terry Savage, the longtime chief executive then chairman of Cannes Lions, after this year’s festival, which was annouced in December 2017.
Ascential (formerly Emap) bought the festival in 2004 for £52.5m. It went on to buy the fashion trends intelligence service WGSN (from where Papa was appointed two years ago) in 2005, media advisory company MediaLink in 2017 and advertising research specialist WARC this year.
This story was updated at 8.45am on 13 July.