Must take: credit card and gps. In Paris dont waste too much time in the day at the eiffel. Its much better at night. Dont miss the night bus tour its the best in paris. Also dont shy from booking an uber there.
Bus passes/metro passes will be available respectively for 3 days and a week.. so you can use them which is very effective..
Get a map of all the metro routes(will def helps you with the directions)..
I personally liked Eiffel in the early morning and in the Night..
Hardly 5/10 ppl are around during the Morning..
Also don't miss replica of Statue of Liberty..!! Good Luck with your trip!!
I hope you have made your trip. It would be helpful for travellers if you share the travel details:
1.Route
2.Transportation
3.Weather
4.Budget
5.Places to see
6.Tips for travellers etc.
Happy travelling.