Is it worth buying a city pass like the Paris Pass?

Only if you plan to visit at least two major paid attractions every single day. If you prefer a slower pace, you are better off buying individual tickets.

How do I avoid high ATM fees?

Use a bank card that refunds ATM fees and always select 'decline conversion' on the ATM screen to ensure your home bank handles the currency exchange at a better rate.

How to save money on family travel in Europe

Save money by staying in apartments with kitchens to avoid eating out three times a day and using regional rail passes instead of last-minute tickets. Prioritize one major paid attraction per day and fill the rest of your time with free city walking tours, public parks, and local markets.

Book apartments instead of hotels. Search for 'aparthotels' or Airbnb units with a kitchen. Cooking breakfast and dinner at home saves a family of four roughly $80-$120 per day compared to restaurant meals.
Master the public transit pass. Avoid taxis and ride-shares. Buy city-specific transit passes (usually 24-72 hours) which offer unlimited subway and bus access. Children under 12 often ride for free or half-price.
Buy rail tickets 60 days in advance. European rail companies release deeply discounted 'saver' fares about two months out. Use the Trainline app to compare routes and book early; buying at the station on the day of travel can cost 300% more.
Leverage 'free' museum days. Most major museums have specific days or times (often Sunday afternoons or first Thursdays) with free entry. Check official museum websites before you finalize your itinerary.

Is it worth buying a city pass like the Paris Pass?: Only if you plan to visit at least two major paid attractions every single day. If you prefer a slower pace, you are better off buying individual tickets.
How do I avoid high ATM fees?: Use a bank card that refunds ATM fees and always select 'decline conversion' on the ATM screen to ensure your home bank handles the currency exchange at a better rate.