Italy and France with a 16 year old and an 18 year old: July 2022

To me, a practical itinerary is dependent on the number of nights you have in Europe. Perhaps you have an idea how fast you like to move from your earlier trips? I'd say ten days is short for the three cities you've already mentioned, much less additional places. Fourteen days would give you more breathing room, but don't forget about the half-day or more lost every time you shift hotels.

Most of Italy's quite hot in July, so if there is another destination to be added, you might consider choosing somewhere in France, where the odds of good weather are better.

If they both speak French, spend the 2 weeks in France. NO ONE who has visited Rome or Venice in July would do it again.

I too would stick to France. You will lose about 7 hours door to door getting from central Paris to the centre of Rome. Rome to Venice by train will take a further 6 hours door to door, so that’s effectively 2 days lost out of 10 days in Europe.

Italy in July will be busy and hot.

From Paris, you could have a side trip to Normandy or the Loire valley.

Italy is my favorite foreign country, but for you, with 10-14 days and kids speaking French, I recommend sticking to France.

Paris for 5-6 days, the consider Normandy (D-day beaches and American Cemetery as well as Bayeux). Also, the Loire Valley with its Chateaux for 2-3 days.
Come back and do Italy, plan about two weeks to see Rome, Naples area, Florence and Venice.

Have them watch the pertinent videos on this website to get an idea of what they would like to see and do.

Stick to France. Suggest plotting the route of the Tour de France and, if interested, plot an intercept location so you may be exposed to an event of national pride. Wonderful fun, high energy and a French experience.

The greater the extent to which you get the son and daughter involved, the better the trip will be regardless of the specific places you visit. If they are invested in the planning, they are far less likely to be come "unhappy campers" as some young people are prone to do. Another thing to remember is the amount of time lost changing locations. Not just the actual travel time, but also the time spent packing up, checking out, getting to the train / bus station, finding the new hotel, checking in, and unpacking. Just a thought to keep in mind as you finalize your plans.

"NO ONE who has visited Rome or Venice in July would do it again."

Tom, I think it depends on where you live. Our first trip to Rome was in August. Our British guide talked about how hot it was-it was 89! (We call that Spring!) We still laugh about that, 35 years later. 89 in August is a cool spell for us. I can sweat in Italy just like I sweat at home. And I do remember a time when the only buildings in the southern US that were air conditioned were the movie theatres(and at our high school, the cafeteria and the band room). Or maybe you were referring to the hordes of tourists in the summer?

We took our kids to France when they were in their mid-teens. In addition to Paris we drove to the Normandy beaches, and then to Mont Saint Michel, and then on to the Loire Valley for a chateau visit. We all enjoyed the trip! Another time my 18 year old son and I visited Venice in July. He didn't like it because it was very hot and crowded. The kids were also teenagers when we visited Pompei and its archaeological site and they enjoyed it. My suggestion would be several nights in Paris followed by a few nights in a smaller nearby place that interests you. Then go to either Venice or Rome for a few nights each and perhaps you'll have time to fit in a smaller place in between - especially if you can go for the entire 14 days.

I agree with the others about skipping Italy, or at least skip the cities like Rome and Venice. Too hot and way too crowded.

We took our daughters to Italy for their graduations ( one from college, one from high school) in late June, 2010. Venice is our favorite city in the world, but I would never go in the summer. I did not put it on the itinerary. Nor Rome either. Instead, we visited Verona, Florence, Siena, Cinque Terre, Varenna on Lake Como, and Milan for the ballet at La Scala. It was a great trip.

But for you, with the interest in Paris and France, I would stick with that country, or maybe dip into Switzerland if you want. Have the kids watch some of the Rick Steves travel shows ( they are on this website) to get some ideas.

https://www.ricksteves.com/watch-read-listen/video/tv-show

I particularly recommend the new French Alps show, which is featured on that page. It covers Lyon and Chamonix, and will make anyone watching say "I want to go there!" Our daughters loved Chamonix (on a separate trip from Italy) and so did we.

These young adults will be more engaged if they help plan the tour now. They no doubt have plenty of computer and Internet skills for invaluable research, especially if they are part of the decision-making.
Paris has had heat waves in mid-summer the last two years so air-conditioned lodging could be helpful (plus quieter than sleeping with the windows open.)
One strategy would be to fly trans-Atlantic and immediately connect south to Marseille. That city is not the tourist's idea of romantic France but is very lively and multi-cultural. Then do a few side trips by train. Move to either Aix-en-Provence or Avignon (Aix-e-P is a university town) as a second base for a couple of nights. Then high-speed train north to Paris as a base for the rest of your two weeks, again engineering day trips. Fly home from there.
This strategy is efficient because it saves the time and cost of returning to the original destination airport. Plane tickets won't be any more expensive than a simple round trip as long as you use a multi-destination flight search to arrange the itinerary. It could be done in the opposite direction by starting in Paris and then heading south by rail. Paris provides a more comfortable departure for North America while Marseille's airport, while useful, would probably require an early-morning take-off and connection somewhere.

PS: Your "kids" are certainly equipped to go off on their own excursions if you and they have different ideas for daytime activities. Share your adventures over supper. A hidden aggravation in travel is too much togetherness.

10-14 days is short for that much coverage. I am on the younger end of the RS' folks (almost 51) with teens that age, and have bene to those places in July (during a heat wave) - just for where my perspective comes from. I have found 4 full days in a city top be the right amount. For both Paros and Rome, by the end of the 4th day I was satiated and/or ready to do something new. Ive done the Normandy/Mt St Michel version people mention and it was much more satisfying than I imagined (I chose it more bc it 'fit' into the larger trip than because I had always wanted to see Normandy). My then 13yo daughter loved the American cemetery, the Bayeux Tapestry (that was cool!), and MSM (we arrived at 5pm and it closes at 7pm, and had the place almost all to ourselves - in July! Then ate dinner on the 'rock' and drove back to Bayeux, arriving by 9:30. I got that trick from RS and have touted it since). We spent 4.5 days in Paris, ½ day traveling to Bayeux, and 2 full days there. On another trip (with all three kids), we were in Paris for 3 days, then went to the Loire Valley for two full days, then further south. The Chateaus were fun, but I think the other two kids might have liked Normandy better. Loved Rome. Spent 4.5 days and did all the things.
I would choose 3 places: two cities and one more rural sandwiched in between. Cities are tiring because of the crowds and the desire to pack in all the things (exhilarating and frazzling). I find places like Normandy or Loire or Tuscany (etc, wherever) to give more breathing room before going headlong into another city. You could fly into Paris, spend 4 days?, train to Normandy for 2-3, train back to a Paris airport for flight to Rome, 4.5 days there, and then home...

Thanks for all the great info! My first trip to Europe was 14 days on a guided tour and we did Rome, Florence, Venice, Lucerne, Paris and London and I felt like it was a good amount of time. I would have liked another day in Paris and London. I would probably skip Florence and Lucerne in the future, just not a fan. I am gonna take your advice and have the kids look at the videos and choose where they want to go.