The behaviour of complex smooth vs 1-dimensional real smooth functions is discussed in a previous question.
In "Complex Analysis as Catalyst" by Steven G. Krantz, the Cauchy integral formula is generalized from holomorphic functions to continuously differentiable functions from $\mathbb{R}^2 \rightarrow \mathbb{R}^2$:
$f(z) = \frac{1}{2\pi i} \oint_{\partial \Omega} \frac{f(\zeta)}{\zeta-z} d\zeta - \frac{1}{2\pi i} \iint_\Omega \frac{\partial f/\partial \overline{\zeta} }{\zeta-z} d\overline{\zeta} \wedge d\zeta $
Does this integral formula imply any rigidity for functions that are only continuously differentiable ($C^1$) but 2-dimensional ?