What's holding France and everybody else back from creating the next Google, is that there is only ever one Google.
Looking at the list of largest tech companies globally, there are perhaps four dozen very large tech companies in the West. Based on their ages, one might get founded in the entire West in a given year on average during the modern transistor era.
Simply put, there aren't going to be 27 Ubers or Googles or Microsofts. There is one of each. So for France (or any given country) to produce these types of companies, they have to beat everyone else racing to produce that outcome. The odds are extraordinarily low, no matter what you do, once you start adding in all the hurdles, as time is of the essence since it's always winner take most.
What countries like France can do, is produce a lot of mid-size tech companies that can take advantage of local and regional opportunties better than large foreign firms. The long-tail opportunties, in other words, that require being down in the minutiae.
As an example, you'll never produce larger global retailers than Walmart or Amazon, no matter what you do, if you're a given country in the EU. That doesn't mean you can't occasionally beat them at their game on your turf however (as retailers routinely do around the globe). It heavily depends on the nature of the tech / segment in question. The reason that works that way, is similar to why Google, Microsoft, Apple, Uber, Intel, Cisco, et al. have done so well as global giants, whereas SAP hasn't been vanquished in the European market by the likes of Oracle and Salesforce. Local relationships are immensely important in some areas of tech. If you're Google, it's the ability to dominate the huge US market, derive immense profit from that base, and rather easily perpetually project outward at claiming pieces of market share all over the planet. That concept only fails if the US economy does, there's nothing France can do to compete with it, unless the EU wants to entirely integrate (they don't and never will, national sovereignty is too important). The real local competitive advantage for a France is in tech where there is friction that provides an advantage based on culture or location. They're not going to produce the next Google, ever, and they shouldn't be aiming for that.