Originally Posted by RedeyeAV8r

From Cambridge, take the Train to Kings Cross Station (one of the stations bombed by terrorist btw last year). From Kings cross Station take the Circle Tube (Mind the Gap) to Waterloo which is right the Thames from BIG BEN and across the street from the "Eye" of London. From Waterloo STA, as MD11fr8 said, take the Euro Star high speed train to Paris.(3 hours 18 minutes. From Cambridge the trip will cost (my guess ) roundtrip 160 lbs or $ 320 usd. If you are trying to do it in a day you will be pressed for time for any real visit with your daughter. I would go over the night or before if possible and come back the next morning. You shouldn't need a french visa because you will be a tourist, key word is "Shouldn't" Enjoy.