Pierre Fornay was the Premier of the Republic of France in May 1887 when Mexican Chief of State Benito Hermión claimed that France was plotting to attack the U.S.M. in league with Guatemala and New Granada. Fornay denied Hermión's charges, claiming that the documents and letters Hermión produced as evidence were forgeries, as indeed they later proved to be.
Sobel does not say how long Fornay remained in power, but by February 1888 he had been succeeded by Antoine Phillipe. Fornay does not appear in Sobel's index.