thank you very much for you quick and thoughtful answers for all my questions regarding to tickets and travel using Paris transit.
To come out a best solution from a complicated system is very time consuming for new visitors. Thanks to Ben for your enormous attentive information, I think i had a better idea now. I had learnt a lot seemed like I was starting doing a literature review for a new research project.
With the new Navigo pass it make travelers much easy to buy tickets to visit Paris !
A suggestion for making easier to buy Navigo. I think It is not necessary to have a photo on the Navigo week pass, for such a short validation. Maybe a photo for a month pass is proper .
Great appreciation to Ben for his excellent help