Headed to London for a family reunion soon, but booked the Eurostar to Paris to take the sister to DLP since she's never been. It's just a day trip - taking the 1st train in (arrives at Gare du Nord around 9:30AM) and the last train out (leaves Gare du Nord at 9:10PM). Any suggestions for a plan of attack for the day? I have not been since 2013 (though I've been to Paris many times, just usually skip the park). What's new that I shouldn't miss?