Two projective nonsingular complex algebraic curves X and Y defined over th
e field R of real numbers can be isomorphic while their sets X(R) and Y(R)
of R-rational points could be even non homeomorphic. This leads to the coun
t of the number of real forms of a complex algebraic curve X, that is, thos
e nonisomorphic real algebraic curves whose complexifications are isomorphi
c to X. In this paper we compute, as a function of genus, the maximum numbe
r of such real forms that a complex algebraic curve admits.