We discuss the scattering of relativistic spin zero particles by an infinit
ely long and arbitrarily thin solenoid. The exact solution of the first-qua
ntized problem can be obtained as a mimic of the nonrelativistic case, eith
er in the original Aharonov-Bohm way or by using the Berry magnetization sc
heme. The perturbative treatment is developed in the Feshbach-Villars two-c
omponent formalism for the Klein-Gordon equation and it is shown that it al
so requires renormalization as in the Schrodinger counterpart. The results
are compared with those of the field theoretical approach, which correspond
s to the two-body sector of the scalar Chern-Simons theory.