Not sure how that would fly outside of the US. In France we have probationary periods but I have never heard of a company hiring multiple people for a full time role (CDI) and then laying off the ones that aren’t the best fit after a couple of months. That sounds to me like a way to get in a bit of trouble - legally, socially, with unions - in the employment context here.
Would be interested in learning whether there’s a French company that does anything like this - maybe a half dozen CDD’s with the express commitment to hire one of the six on a CDI after three months? But who is leaving a CDI on that sort of bet?