2020, Djourou joined Danish Superliga club FC Nordsjælland on a two-year deal. He made his debut for the club in a Danish Cup match against FC Græsrødderne. On 4 June 2021, Djourou announced his retirement at the age of 34. He cited physical pain from playing, as well as business interests in a football academy and a podcast. International career Youth career Djourou represented Switzerland up to the U21 levels. He was a member of the Swiss under-19 squad that reached the semi-finals of the 2004 European Championships. Following the end of the tournament, UEFA said about Djourou's performance, saying: " A substitute in Switzerland's first three matches, he produced a fine display after coming on against Ukraine and was his country's best player in the semi-final defeat by Turkey." He went on to make eight appearances and scoring once for the U19 side. The following year, Djourou was called up to the Switzerland U20 for the FIFA World Youth Championship in Netherlands. He went on to play three times in the tournament, as the U20 side were eliminated in the Group Stage. In September 2006, Djourou made two appearances during Swiss U21's qualification campaign for the UEFA European Under-21 Championship qualification. Senior career Having been eligible to play for Switzerland and Ivory Coast, Djourou opted to play for Switzerland. He made his senior Switzerland international debut in a friendly away to Scotland on 1 March 2006, coming on as a half-time substitute for Valon Behrami in the 3–1 win. Djourou was called up to the Switzerland 2006 FIFA World Cup squad, despite not playing in the qualifiers. Upon being called up, he said: "It's going to be amazing because I was born in Ivory Coast and still feel there is an African part of me. My biological mother still lives there and I have a lot of contact by telephone with my family there, so if I am picked to play for Switzerland against my 'other country' it is sure to be a special moment. It's always something special to be the youngest in the team but I'm not taking that aspect too seriously as we're here to play football and for that age doesn't really matter," Djourou said. "My own goal for the World Cup is just to play and now I have to prepare myself to show the coach that I'm ready." His father successfully predicted that