My family is traveling to Italy and France in two weeks. We will begin in Rome and end in Paris over 3 weeks traveling by trains. We will never be renting a car. We have an airport transfer picking us up at the airport in Rome and another taking us to the airport in Paris. All of our other transportation will be trains, buses, and metros. We have three children : ages 3, 5, and 7. We don't want to lug around carseats from city to city if we don't need them. I am trying to find out if we are ever going to need them on our trip. Thank you.
This is a touchy subject on this board. As the parent of a 6 year old who has been to Europe twice (the kid, not me), I would say no. You're not likely to be able to fit the car seats on a shuttle van anyway.
Others will scream that it's the height of irresponsibility to go without car seats.
I agree with Doug though there are lots of people who would disagree. We have been in lots of countries in Asia, S. America and Europe and have always left the car seats at home. They become just another luggage item to have to deal with and wont be of much use to you on a tram or train.
Rereading your message - since all your transport except to/from the airport is trains/buses/and metro, I would say definitely not. My mindset is that you cannot have perfect safety and carrying carseats just for the flight and the 2 rides is not worth the hassle. However, this is just my opinion and you have to be comfortable with the decision you make.
As in the U.S., there are no seat belts on trains, buses or metros. So there is no way to anchor the car seats. Are the car seats completely functional if they can't be strapped in? In Italy, your 3-year old can ride for free on the train but with no seat (that's the rule). But, usually, there are extra seats. I haven't visited that rule in awhile so if you want, I can re-check it.
One thing to check into is whether or not the transfer services can provide car seats. We used one in Rome (when there with our 22-month old) specifically because they could. We also took a few taxis and didn't use one. Considering how much luggage you're likely to have already, I personally wouldn't bring one (or 3), but, obviously, that decision is up to you.
For those who ARE renting cars in Europe and travelling with children, you can get a good survey of what country requires what safety procedures by clicking here. However, you should always confirm the information with local rental agencies....all will be able to rent you childrens' car seats if necessary.