We present an algorithm for simulating reverse Monte Carlo decays given an existing forward Monte Carlo decay engine. This algorithm is implemented in the Alouette library, a TAUOLA thin wrapper for simulating decays of τ-leptons. We provide a detailed description of Alouette, as well as validation results. Program title: Alouette CPC Library link to program files:https://doi.org/10.17632/w2z5w546c5.1 Developer's repository link:https://github.com/niess/alouette Code Ocean capsule:https://codeocean.com/capsule/9167021 Licensing provisions: LGPL-3.0 Programming language: C, Fortran and Python Nature of problem: Perform reverse Monte Carlo decays. Solution method: Invert an existing forward Monte Carlo engine using the Jacobian backward method. Apply the algorithm to τ decays generated by TAUOLA.