It is indeed Bardot-esque, and the smock top is not only cute for the beach, but would make an awesome sundress, if you added some length. You could belt it, or not. I'm thinking white cotton eyelet embroidery, but I see everything in eyelet embroidery lately since I found a feast of it in a store in Bali recently (more on that for another post).
Looking at this pattern I started wondering, what did they make swimsuits out of before lycra and spandex? The fabrics suggested don't mention synthetics at all - it's all denim, gingham, broadcloth, pique etc. so it must be pre-1960s.
If you made this suit in cotton (lined of course, no see-through-ness allowed) would it be for swanning around in only, or would it still be appropriate to bathe in it? And if you bathe in it, how might the fabric behave? I can't imagine bathing in denim - cotton or linen maybe, but the lack of stretchiness or ability to re-shape after being wet bothers me. I know early swimsuits were often made of woollen knits but I feel that wool would have had more capacity to spring back into shape (though it must have been scratchy).
Clearly I'm no expert in vintage swimsuits. Does anyone else know?