Epsiloon was launched by a dozen journalists, most of whom left Science et Vie in March 2021 to preserve their editorial independence. Reworld Media claimed nearly one million euros from Mathilde Fontez and Hervé Poirier, editors of Epsiloon, for "defamation", as well as from their publisher Unique Heritage Media (UHM) for "unfair competition and parasitism" A Nanterre judicial court rejected Reworld's "all of its claims", ordering it to compensate the other party for legal costs.