Beware purchasing tickets in advance

Sorry to hear that. Were you supposed to fly today? They need to provide alternative flights. If you look on line for dates and schedule that would suit you, you could ask to be revoked to them ( if they are not full). Alternatively, ask if they will book you onto another airline, or price out alternative flights and see what your travel insurance will cover.
I know I never understand people looking for train or bus tickets...or even museum tickets months and months in advance. I book the most vital attractions only a little in advance (or the Alhambra or Last Supper earlier as they do sell out). But then I travel solo, so less difficulty.

Prepandemic that was always good advice. I'm curious how the updated books will address pre-planning strategies.

Not to rub it in, but because of flight delays we have experienced since COVID, we never plan anything for our first day, because we might not get there.
Perhaps you can leave a day earlier - what is your airline offering? Do you have trip insurance, or credit card protections?
So sorry, and good luck!

You’re trip insurance should cover it and all things lost due to a canceled flight

We were supposed to travel tomorrow 6/24. they booked us for 6/25. It impacts 2 events I had planned. Leaves us with less time in Venice overall. Just very disappointing. I'm hopeful the hotel will refund our money for the previous night. The airlines are apparently not responsible for any expenses incurred by travelers except the flight itself.

Hopefully your trip insurance will cover the cost of the tickets you couldn't use. Over the years we've realized the prudence of not planning anything requiring advance tickets for the first couple of days. But some things just do require those tickets to be purchased weeks or even months in advance due to demand. We try to schedule those later in our stay.

When that happened to us in 2021, the Lucerne hotel was very generous and did not charge us, because we booked directly, they said. We had to jam in our Lucerne activities into 1.5 days. After that, we added a day at the front end. Last year's trip to Munich we arrived six hours late, getting to the hotel at 1:00am. I was very glad we weren't going on to Salzburg until the next day, and hadn't purchased train tickets ahead of time.
So sorry- it is maddening!

Unfortunately what happened to you is a new lesson for us - have a buffer day or two. We have a Norwegian cruise booked for next May. We’ll be going 2 days in advance, just in case.

I'm sorry that happened to you. Very frustrating.

I would tend not to book museums or experiences on my arrival date. Beyond that, It's really a catch 22. If you don't book in advance, many places will be sold out when you arrive.

Did they tell you why the flight was canceled? Was this a flight from the US to Europe on Air France? Depending on the reason for canceling at this late date, you may be entitled to compensation under EC 261 under Articles 5 and 7. Ut it totally depends on the reason for cancellation. Strikes, bad weather, no compensation. Mechanical problems, lack of pilots or cabin crew—compensation.

https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX%3A32004R0261

This is not a trip cancellation claim because your trip wasn't cancelled, just your original flight was. If you've got insurance, this would be a trip delay claim. You'll be reimbursed for the pre-paid and non-refundable expenses you incurred for things you couldn't do because of the common carrier's delay in getting you to your destination. Collect proof of what you paid and copies of the cancellation policies showing that you can't get your money back.

I've taken 4 round trips in the past year and have a 5th scheduled for September. Not one left or came back as scheduled. Both to Europe last year were changed by a day, but with enough notice that we could adjust, hotel and car rental reservations. In January, my flight home from Chicago was cancelled and I was forced into a 24 hour layover. Chicago is nice, but not in January. In April to Rome our flight time changed multiple times in the weeks leading up to the day of departure resulting in an arrival several hours later than expected. And now my flight to DC has been changed to 2 hours later meaning I was smart not to buy baseball tickets in advance.

Delta is a SkyTeam alliance partner with Air France. Were ALL the seats on Delta’s flights to Paris fully booked? I don’t know your home airport but if Delta goes there, Air France couldn’t have arranged for you to fly Delta to JFK, BOS, DTW, ATL, MSP, SLC, SFO, LAX, or SEA in order to connect to a Delta flight to Paris CDG?

I think it’s always a slight risk to pre-pay for something in the first day or so of your trip. I always just figure that in the total cost of the whole trip, it’s probably a small percentage. But definitely check with travel insurance to see if you can make a claim for Trip Interruption. And of course you can’t put a monetary value on disappointment.

By the time you arrive a day earlier, which costs a day in a hotel plus the cost of food for the day, it can often be a wash if you consider the cost of excursions/tours.

On the other hand, spending hundreds of dollars on a private tour on arrival day might not be a good plan; I generally plan expensive private tours for subsequent days, wherever possible, opting for lower-priced activities on arrival day. Or, I use a pass like the multi-day museum pass in Paris, and plan it so that it covers arrival day plus all the subsequent days of my stay in that locale.

The EU has new rules about airlines' liability in the case of flight cancellations; my understanding is that similar policies will be in effect in the US in the near future. It might be worth a bit of research to see if the mentioned flight cancellation can result in some compensation from the airline.

What is a bit scarier is if a flight gets cancelled or modified when going overseas to join a tour or a cruise. We were on our way to Florence to join the RSE Best of Tuscany tour in late May, and I found out that somehow we were no longer booked on the final leg of our flight into Florence. I spent a couple of days on the phone with United, and got us back on the flight, but when the United rep told me, "You can just fly in the next day," I wasn't happy at all--didn't endear me to United Airlines. Had we missed the first day of the RSE tour, I wouldn't have been pleased.

We lost a day in New York because Southwest stranded us in Milwaukee for 24 hours. The airline was terrible and so understaffed they had ramp people working ticketing and it tool 2 1/2 hours of begging to be given anything more than a refund and "good luck". But both the Statue of Liberty tour company and our AirBnB were both very understanding with the tour easily being rebooked for the following day and our AirBnB adding a day onto the end and not charging us at all for arriving a day late! This year I'm booking the first couple of days in Paris at a hotel with free cancellation and have bought a changeable train ticket out of Paris just in case there are last minute changes because of a delayed flight or strike.

There are absolutely things that have to be booked in advance or you simply won't get in to see them. It is very sound advice. If I hadn't booked the Borghese Gallery months out we wouldn't have been able to go and it was a favorite. If you book it too close to your arrival though and the airlines mess with your flights that is where the problem is. Some sights you should always book ahead, but you need to make sure you don't book them too close to your arrival.

If this happens can you show proof of your new itinerary to the Museum Ticket Office for an even exchange or cancellation? I agree booking in advance is ideal. Actually they do hold back times at times for last minute bookings.