After researching this question outside our community, I have come to a strange realization:

• million is a unit name and is interpreted as such when isolated

  • un million un works like un kilo deux (1.2kg) or deux mètres dix (2.10m)
  • in French, subunits used this way are limited to thousandths, so the interference runs from 1 to 999
  • but when actually counting an explicit unit as in un million un chats it is understood as 1,000,001.

• as million is a noun, something else occurs at the number preceding the one in my original question.

• we can say in French 999 999 chats as well as 1 000 001 chats but not 1 000 000 chats... the latter as to be said 1 000 000 de chats, the same way we have to say un kilo deux de carottes

After researching this question outside our community, I have come to a strange realization:

• million is a unit name and is interpreted as such when isolated

  • un million un works like un kilo deux (1.2kg) or deux mètres dix (2.10m)
  • in French, subunits used this way are limited to thousandths, so the interference runs from 1 to 999
  • but when actually counting an explicit unit as in un million un chats it is understood as 1,000,001.

• as million is a noun, something else occurs at the number preceding the one in my original question.

• we can say in French 999 999 chats as well as 1 000 001 chats but not 1 000 000 chats... the latter as to be said 1 000 000 de chats, the same way we have to say un kilo de carottes