  For any decomposition of a Lie superalgebra $\mathcal G$ into a direct sum
$\mathcal G=\mathcal H\oplus\mathcal E$ of a subalgebra $\mathcal H$ and a
subspace $\mathcal E$, we construct a nonlinear realisation of $\mathcal G$ on
$\mathcal E$. The result generalises a theorem by Kantor from Lie algebras to
Lie superalgebras. When G is a differential graded Lie algebra, it gives a
construction of an associated $L_\infty$-algebra.
