A pure French has "core values". He is proud to be French, a bit arrogant, a bit thinking like his country is big ("la Grande Nation"), the source of all the enlightenment philosophers, that English has more than 30% of its words directly taken from French and that without French cuisine and mode, and his magnificent country for the people to visit, the world would not be a place to live, can discuss without start and end on any subject and do not listen anyway to your answers. (I think there are many more core values, but I forgot them)
It means that you can be pure French with Algerian, Moroccan, Chinese, whatever you want and have, roots. You just need to believe the core values and you are definitely French.
Sometimes my wife tells me that I am a stupid French.
You make the EU actually use French as a working language, even though German has far more native speakers in Europe and is also a working language nobody insists on using. You also make the whole parliament move to Strasbourg every other week for no reason.
But at least you are comitted to the EU, so as long as the ECB stays in Frankfurt, we are fine with your special treatment. Although you could tip better ...
How many of those 50% new Belgians had all Belgian ancestors? And not some French, Dutch, German, Italian .. person somewhere up in their family tree?