  Consider a $k$-linear Frobenius category $\mathscr{E}$ with a projective
generator such that the corresponding stable category $\mathscr{C}$ is
2-Calabi--Yau, Hom-finite with split idempotents. Let $l,m\in\mathscr{C}$ be
maximal rigid objects with self-injective endomorphism algebras. We will show
that their endomorphism algebras $\mathscr{C}(l,l)$ and $\mathscr{C}(m,m)$ are
derived equivalent. Furthermore we will give a description of the two-sided
tilting complex which induces this derived equivalence.
