If you aren’t too tired, I always recommend walking around the city. It is the best way to see everything, and really get a feel for the city. This was how I found my favorite hole in the wall deli, that had amazing bakery!
Paris is a city with many hidden gems, but you have to walk around to find them
2. Vélib’ bike rental system:
Paris is bicycle friendly and renting a bike is an easy affordable way to explore the city. Short rides of up to half an hour are free, but any length of time is a good deal.
France fortunately didn’t outlaw UBER like a lot of other european countries. My friends and I would split the ride 3 ways, so it never ended up being more than 2 € each. Easily the cheapest and most convenient way to get around the city.
If you are only in Paris for a few days, I recommend getting a “carnet” of 10 tickets. It works out to be around 14.10€. If you are planning a longer stay, it might be worth getting a weekly pass. These are reloadable and similar to BART cards.
The bus system is sort of a hassle to figure out, but if you want a cheap alternative, this is the way to go!