The Paris-based exchange had originally planned to launch a spot carbon market in March in conjunction with French state-owned investment bank Caisse des Dépôts et Consignations and pan-European exchange operator Euronext.

But the French emissions allocation registry – detailing how many CO₂ allowances each company will receive – was not finalised until mid-May; hence the delay, says Jean-François Conil-Lacoste, chief executive of Powernext.

Powernext Carbon will launch into a competitive