A temporary, and often insincere, reconciliation. The phrase refers to Abbe Lamourette, who was (briefly) able to unite the various factions of the French National Assembly in 1792. Of course, they couldn't stay in agreement for long—it was all just a Lamourette's kiss.
See also: kiss
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.