On the right is the Monaco in all its pretty pinkness.
My mom asked this very good question, because I've mentioned them a few times in my posts about Paris. A Monaco is a drink they make with beer (over there it's typically Kronenburg 1664). The most common recipe I found online was:
1 splash grenadine syrup
2/3 glass beer
1/3 glass 7-Up® (I think they used a lemonade/limeade there.)