Proudhon made a few comments in his Carnets, expressing anger at Marx and suggesting a work he might write. But all that we seem to have are some marginal notations, reproduced in the third volume of the combined edition of Proudhon's Système des contradictions économiques (published under its subtitle Philosophie de la misère) and Marx's Misère de la philosophie published by the Groupe Fresnes-Antony of the Fédération Anarchiste in 1977.

The extent to which Marx was not yet a figure to be reckoned with during Proudhon's lifetime is perhaps reflected by one of the few French reviews I was able to turn up. In La Revue indépendante, a journal associated with Proudhon's intellectual rival Pierre Leroux, Proudhon's book is critiqued generally, with a short and generally celebratory passage on the publication of Marx's book added as an example of the critiques leveled at Proudhon—but Marx is misidentified throughout as Carl Marr.

If you're interested in a more modern assessment of Marx's critique of Proudhon, you might find Iain McKay's paper on "Proudhon’s constituted value and the myth of labour notes" useful.