All credits goes to the YouTube user JunpeiCollection.
Done few tries and worked very well.
Just remind to select the same stage (Heavenly Garden) because don't have the walls and the punch configuration on the normal (square on left punch, triangle on right punch) The TAG button I recomend on circle to do only this trophy.
And off course, need select Paul and Forest Law.
The explanation just see the video.
Forest "Poison Arrow" move, quickly TAG, Paul's right punch (2 times on the right timing) and Forest left punch on the right timming again.
PS: Done in the practice mode.