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?

Isn't it frustrating??

I used to fly European airlines including Air France. Stopped that about 10 years ago when we were impacted by a strike. I've had better luck on US carriers - actual metal, not code shares. It could be just my perception, but I've been happier with United and American to the UK and the continent than I was with Lufthansa, British Air, Air France, and Iberia. If nothing else, the communication from the US based carriers seems better. You can't protect against European general transportation and related strikes, but at least I am not monitoring a foreign carrier's negotiations and strike possibilities.

That said, flying SAS next week. So far, one flight change and one re-seat.

I have had very good luck with Asian carriers - Cathay Pacific, Singapore, and ANA. I book those airlines in preference to US based carriers.

I have learned to add a buffer day and try not to make reservations or buy tickets for 1st or 2nd day of arrival, saving those special events for several days into the trip. It's not always possible, however.

I don't think there is valid blanket "buy in advance" vs "don't buy ahead" advice. (I find Rick over-simplifies frequently. Or, maybe the advice is just not sufficiently nuanced. Or, is old.) Sometimes, for popular museums/exhibits, it is possible to monitor ticket availability and purchase as the timings and availability become sparser. I've done that, pre-booking a few days (or hours) ahead when already at my destination. Some places, like the Borghese Gallery, require advance reservations due to strict limits on numbers. Those place often need to be purchased months in advance.

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.

If I can’t fly direct to a location abroad, I always book thru an intermediary country or city outside the US. So many US flights are cancelled or delayed. Often the direct flights to Europe, Asia, Oceania are one flight a day, back and forth. The carriers have every incentive to keep the plane in the air if at all safe. No need for the concerns with a US flight schedule where bad weather in one location can impact the entire network. Once in the overseas destination, Europe (for example), if there are problems with a second leg of flights, there are often other options like train.

That’s easy for me to say as I fly out of Chicago with many direct flights and as a retiree, I often have less stringent time/date requirements than many. I have had to be creative in booking at times to follow my “get out of the US before a second leg” dictum. I was connecting thru Hong Kong to Australia several years ago for multiple trips. Actually worked quite well for me, and I preferred that to connecting in a US West Coast city when I didn’t trust that the US networks would run as scheduled.

I’m afraid there is no sure-fire beat-the-system answer, however.

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.