Is it possible to experiment with a universal income?[L’expérimentation du revenu universel est-elle possible ?]

In a blog entitled "Revenu universel, l'impossible expérimentation" [Universal income, the impossible experiment], I underlined the limits of current and future experiments with a universal income[1]: samples that are too small and unrepresentative; the limits intrinsic to a lottery (absence of balancing effects on the labor market; an absence of "peer effects"[2]). Clément Cayol responded to my piece on the website of the Mouvement Français pour un Revenu de Base [French Movement for a Basic Income] ("M Allègre : les expérimentations de revenu de base sont un chemin possible vers l'instauration [Mr Allègre: Experiments with a basic income are one possible path towards establishing it]. Cayol proposes experimenting with a universal income on "saturation sites" (for example, an employment catchment area). The idea would be to select certain employment catchment areas as a treatment group (e.g. Toulouse and Montbéliard) and to use areas with similar characteristics as control groups (Bordeaux and Besançon?). By comparing differences in behaviour between the two groups (in terms of employment, part-time work, wages, etc.), we could identify the impact of a universal income. An experiment like this has taken place in a Kenyan village. [First paragraph]