Mafoumbi made his senior debut on 26 May 2012, starting in a goalless home draw against AC Amiens. On 12 April 2013, he appeared with the main squad in a goalless away draw against SM Caen for the Ligue 2 championship, but remained as an unused substitute.[5]
On 23 July 2014, Mafoumbi joined US Le Pontet, also in CFA.[6]
On 25 November 2015, Mafoumbi signed a contract with Bulgarian side Vereya.[7]
On 20 July 2017, Mafoumbi signed a two-year contract with English League One side Blackpool.[8]
He joined League Two club Morecambe on loan for the second half of the 2019–20 season on 15 January 2020.[9]
Mafoumbi was released by Blackpool in June 2020.[10]
After spending some time in Malta with Mosta, Mafoumbi joined Luxembourg-based side Differdange for the 2022-23 season. In October 2022, he pledged himself on a part-time basis for the newly-formed English Lower League side AFC Crewe.[11]
International career
Mafoumbi made his international debut for Congo on 12 October 2012, playing the entire second half in a 0–3 friendly loss against Egypt. On 8 January 2015, he was included in Claude Le Roy's 23-man squad for the 2015 Africa Cup of Nations.[12] Mafoumbi made his debut in the competition on 17 January, starting in a 1–1 draw against Equatorial Guinea.[13]
^"Entraînement du mardi" [Tuesday training] (in French). Lens' official website. 10 August 2010. Archived from the original on 22 January 2015. Retrieved 22 January 2015.