As much as this could be lovely, this may be over-ambitious. If you can go to Paris, my advice would be to visit, have some great patisserie and good food, and if you want/can, gift yourself with one luxury item: Bag, scarf,...
Then, or before, to overhaul your wardrobe, you should focus on some imperatives:
- Good quality fabrics and cuts. Much better than cheap quantity. Favor cottons, silks, wool, and great quality blends and synthetics.
-Get the right basics, around which your silhouette is created: a flattering pair of jeans, a good blazer, some cottons t-shirts, a mariniere (if you want French style), well cuts black dress pants, dresses in the shape that suits your build (wraparound if your are an X, A-shape if you are a H or A...), some button ups, only if they sit correctly on your boobs (if not, do not bother)... A well fitting leather jacket too!!
-Accessories: at least a good quality belt, medium width, with a visible but not overbearing buckle. Scarves: splurge a little on those if you can. Very large silk ones are to die for.
You can have all that in British shopping center, they have many French brands, even if some of your basics can really be brought at British brands. See if personal shoppers are still a thing, they can be quite helpful when correctly reigned in.