The magnetoelec. effect on a (001)orthorhombic cut Cu-Cl boracite crystal (Cu3B7O13Cl) shows linear and 2nd order components. At 4 K, with P3induced = a33H3 + (b311H12 + b322H22 + b333H32)/2, one obtains: a33 = 1.2 * 10-13 [s/m], b311 ~ 0, b322 = 3.6 * 10-19 [s/A] and b333 = -1.2 * 10-19 [s/A], the signs being understood relative to one another. These results, together with the observation of ME butterfly loops, corroborate magnetic point group m'm'2, as deduced from magnetic torque measurements (M. Haida et al., 1975).