  We prove here a quantitative $h$-principle statement that applies to
isotropic embeddings of discs. We then apply it to get $C^0$-flexibility and
rigidity results in symplectic geometry. On the flexible side, we prove that a
symplectic homeomorphism might take a symplectic disc to a smooth isotropic
one. We also get a $C^0$-rigidity result for the action of a symplectic
homeomorphism on the reduction of a coisotropic submanifold.
