My researches on the 1813 and 1814 campaigns indicate that ALL the standing units in Italy were taken out of Italy and sent to the reforming Grande Armee. The Kingdom of Northern Italy had to completely rebuild its army from scratch. this comes from Général de division Comte de Vignolle's account of the 1813-1814 campaigns.

There were also a number of units withdrawn from Spain, but I'm working on memory from my researches and cannot recall the source. Irrespective of these few units, and the numbers were not terribly large, no more than 20-30 regiments total from all sources, the vast majority of the Grande Army reformed in 1813 came from new recruits and the mobilization of the National Guard. I believe I discussedthis in depth in my book on the Dresden campagin.