Towards a complete gamma gamma -> 4 leptons Monte Carlo

The total cross-section of the gamma gamma --> 4 leptons process is known t o have a large constant value at high energy, but a complete and exact calc ulation of related differential spectra does not exist yet. However a compl ete study of the process is important at NLC for luminosity measurements or for background estimations. We here report on our various steps in that di rection, including the implementation of a first new calculation of helicit y amplitudes in a Monte-Carlo generator.