Paris to Rome by car?

I don't know if it's doable, not having done it myself. What you do need to be aware of is that there will be a hefty charge for renting in one country and dropping in another. If you drive you will need an International Drivers Permit (IDP) which is available at AAA.

It's totally doable and, with the right weather, it can be the driving experience of a lifetime. Check this route suggestion. It is of course much longer than the direct highway route, but it has many high (9000ft or plus) mountain passes with stunning views. http://goo.gl/maps/GCK7 (Google Map Link) This is a 1300 miles itinerary, half of it are highways (Paris-Chamonix, Bolzano-Roma) but the rest is a collection of THE most stunning roads in Europe. It fits well a 4-day drive with 3 nights (I suggest overnight stays in Martigny, Munster and Merano) With a car you can gain access to mountain locations where trains or public transportation doesn't reach, and that are free from people crowding.

Excellent, just what i had hoped for. I would like to keep my drive time closer to 15 hours. If I come in from the north (Basil ?) and cut down towards Milan a little sooner am I losing a lot? I know there will be a drop fee and have estimated that.
I do not know anything about a special drivers license. I did not need one in Italy a few years ago and Auto Europe didn't say anything about that.

It is doable but therre are a few things. 1. You absolutely need and IDP in Italy. I met someone who got caught without one in a random traffic stop and she said things got really ugly really quickly. Go to AAA an spend the few bucks. The people at the rental company desks don't really give a rat's rump whether you have one or not, they are not the ones who will be facing the cop! A a matter of fact in 2006 Renault would not give me my lease car in Italy until I showed them my IDP. 2. You will need a vignette to travel on the Swiss autobahns. Depending where you cross you can get it at the border crossing or at gas stations near the border. It is a bit pricey but well worth it. 3. viaMichelin is a good source of routing information. When using it, if you use Lucerne as a way point it will add an hour or so to the driving time but the drive from Lucerne south on the A2 to Como is very easy and just beautiful. If you have some time to spare on this route you can drive the St Gotthard pass road which is one of the most spectacular drives in all of Europe but if you are short on time you can take the tunnel which is also a unique experience but not as spectacular. I hope you have good weather.
Have a great trip.

It is doable but therre are a few things. 1. You absolutely need and IDP in Italy. I met someone who got caught without one in a random traffic stop and she said things got really ugly really quickly. Go to AAA an spend the few bucks. The people at the rental company desks don't really give a rat's rump whether you have one or not, they are not the ones who will be facing the cop! A a matter of fact in 2006 Renault would not give me my lease car in Italy until I showed them my IDP. 2. You will need a vignette to travel on the Swiss autobahns. Depending where you cross you can get it at the border crossing or at gas stations near the border. It is a bit pricey but well worth it. 3. viaMichelin is a good source of routing information. When using it, if you use Lucerne as a way point it will add an hour or so to the driving time but the drive from Lucerne south on the A2 to Como is very easy and just beautiful. If you have some time to spare on this route you can drive the St Gotthard pass road which is one of the most spectacular drives in all of Europe but if you are short on time you can take the tunnel which is also a unique experience but not as spectacular. I hope you have good weather.
Have a great trip.

It can be done. I thought that your idea would take a bit of driving - I just did it in 2 days by train quite comfortably - so I figured quite a road trip. ViaMichelin shows 17 to 22 hours straight through driving so most of what you will see will be the inside of the car. Those hours to make the 1,500 km don't count scenery stops, food or pee stops, or sleep. Tolls will be over €60 with the CHF40 Swiss Vignette. Drop charge on the car will not be small. Fuel will cost at least €160. If you have to top off before taking the car back be aware that Italy's fuel is some of the most expensive in Europe. Do you actually want to get out of the car or will you do it straight through?

You can keep it closer to 1500km by entering CH via Lausanne, heading to Montreaux and Martigny, following the itinerary I suggested but then you head via the Gotthardpass to Bellizona, head back north to Splungen, then drive via the awesome Splugenpass to Chiavenna, Italy, and from there onwards (including opportunities to stop at Como lake along the way). That would bring things close to the distance you want to travel.

I have driven thousands of miles in Europe and with the itinerary you are proposing the views and scenery should be spectacular. Yes, its a lot of driving, but with a roadside picnic or two and photo stops it should be lots of fun. Make yourself a few cds with some interesting European music. Have a great adventure.