That's nice, but we firmly believe almost all "adult" travel locations are great family destinations. It's how you present it to them, how you control their expectations, and how you seek out those activities and locations for them to see and help them appreciate.
Now, that said and out of the way...Paris and Florence we have been to with the kids and absolutely agree that they are great destinations. There is a Davinci museum that is hands on in Florence, and the gelato alone would get my kids to go back! Paris with Notre Dame is quite the attraction for fans of the Hunchback, not to mention the Eiffel Tower and all.
For me, the bottom line is don't fall into the trap of thinking that kid travel has to include people dressed up in costumes, carnival rides or swimming pools. When properly prepared (by reading up ahead of time, given positive expectations, and having their comfort and safety addressed ahead of time) there are millions of places to take you kids that are far off of the typical family vacation map that they will both love and learn from.
A few shots of our kids in Florence.
Florence 1 030 by
efusco, on Flickr
Florence 1 173 by
efusco, on Flickr
Florence 1 172 by
efusco, on Flickr