  The coupling of topological matter to topological Yang-Mills theory in four
dimensions is considered and a model is presented. It is shown that, contrary
to the two-dimensional case, this coupling leads to a breaking of the
topological symmetry. This means that the vacuum expectation values of the
observables of the theory loose their invariance under small deformations of
the metric while the action of the model possesses all the symmetries
corresponding to the case with no coupling.
