The electron affinities of halogens are F = 322, Cl = 349, Br = 324, B = 324, I = 295 kJ mol−1. The higher value for Cl as compared to that of F is due to

Because of  very small size of ‘F’ (than expected) , there exists strong electron-electron repulsions than Chlorine.So addition of electron to the ‘Cl’ is comparatively easy and releases more amount of energy. Hence E.A of ‘Cl’ > E.A of ‘F’