Vintage bike mercier 1949

I am a vintage bike from 1949, it is, I think, the number 49 marked on my frame that says it; precisely, the number marked is 49 0-342. It was mercier who made me. I am "in my juice", I have been cleaned a little, but we can do much better to make me shine, we can polish my wheels (the one at the back is marked phenix), my rims, my spokes, my handlebars, etc... I have all my organs, I am functional (even my doorbell!), and I ride very well. But I would have to review the lighting, mainly the network of wires and maybe the soubitex dynamo. In fact, I realize that my organs have value: my saddle is leather, brand buf, is worth 68 € at ebay, my shell-shaped front headlight, made by soubitex, is worth 18 € at ebay, my rear light soubitex catalux 6 is worth 30 € at ebay (it should be straightened very slightly), my lenervurex aluminum mudguards are worth 30 € at ebay. My saddle is 86cms from the ground, my tires are 650b, I weigh 14kgs. I have 3 sprockets on the rear wheel, they can install a derailleur, it would be great! They can pick me up at maisons-laffitte (rer a) or la rochelle.