Presented as a gift in 1848 to Thomas Francis Meagher from a small group of French women sympathetic to Irish nationalism,[3] it was intended to symbolise the inclusion and hoped-for union between Roman Catholics (symbolised by the green colour) and Protestants (symbolised by the orange colour).
After browsing the “History of Germany” wikipedia page, I found the German Empire that popped in around 1848, which had the the same colors of the modern German flag.