Having come through the youth ranks at Club Brugge, Fonkeu joined Norwich City on a two-year contract on 31 August 2017 following a trial period with the club.[3][4] He was released by the club in summer 2019 following the expiry of his contract.[5]
On 27 June 2019, it was announced that Fonkeu had signed for RC Lens, initially joining their reserve team in the Championnat National 2.[6] However, he played just once for their reserve side and joined Bulgarian First League club Beroe in February 2020.[7][8] He played 3 times for Beroe but was released at the end of the season.[7][9]
Following a trial spell at Grimsby Town, Fonkeu was offered a short-term deal with the Mariners, however this was held up due to delays in obtaining international clearance, and fell through after the departure of manager Ian Holloway.[10] Fonkeu signed for National League club Weymouth on a permanent deal on 30 January 2021.[2] He made his debut for Weymouth as a substitute in a 1–0 home defeat to Notts County later that day.[11] He made 15 appearances for Weymouth during the 2020–21 season.[7] He was released by the club at the end of the season following the expiry of his contract.[12]