Resemblances
Given the superficial similarities between the two flags, it may be surmised that the Italian tricolour formed the basis for the flag of Mexico differenced only in the coat of arms positioned over the white portion. However, the Italian tricolour actually uses lighter shades of green and red and, more important, the two have different aspect ratios; the Italian flag's aspect ratio is 2:3, while the Mexican flag's aspect ratio of 4:7 results in a more elongated rectangular shape. When Italy became a republic in 1946, the Mexican naval ensign was a plain tricolour; for this reason, on demand of the international naval authorities, Italy could not adopt a sole national flag similar to France as it wished.
Given its possible derivation from the French tricolour, the flag of Italy is similar to many flags of putatively similar origins. The Italian tricolour is particularly similar to the flag of Ireland, which is green, white, and orange (a tone very similar to the red used in the Italian flag), but with different proportions (1:2 against 2:3) and the flag of Côte d'Ivoire, in which the colours, orange, white, and green are reversed, while the proportions are the same. Confusion may also exist between the Italian tricolour (particularly when hoist vertically) and the flag of Hungary, which has the same colours positioned horizontally, although with red uppermost.
Read more about this topic: Flag Of Italy