  On a compact oriented four-manifold with an orientation preserving involution
c, we count solutions of Seiberg-Witten equations, which are moreover
symmetrical in relation to c, to construct "real" Seiberg-Witten invariants.
Using Taubes' results, we prove that on a symplectic almost complex manifold
with an antisymplectic and antiholomorphic involution, this invariants are not
all trivial, and that the canonical bundle is represented by a real holomorphic
curve.
