I love how anytime somebody is going on a trip and lists their equipment and asks what to take there are so many suggestions to invest a lot of money in new equipment, a high end bridge camera, expensive new glass, etc. I'm guessing when paying for a trip like this nobody is looking to spend an extra $1500 on equipment. If luggage isn't an issue I would take it all and then when planning each day I would decide on what to carry based on what I think would work best for what I'm going to see that day. Yes, you're going for the memories, but you're also going to have chances for those once in a lifetime shots that you'll never get again. somebody mentioned only needing the good equipment for "wall hanging" shots, well I find that many of those wall worthy shots I take or an vacations.

This gets my vote and I've been to more than 75 countries. Of course all this advice doesn't really take in to consideration what you want to shoot. On a recent trip to Greece and Italy I took similar lenses as recommended here plus a 70-200 F4 which I took over the 2.8 due to smaller size and less weight. The only time I used it was when the Acropolis closed and the only place I could capture it was from distant hills. I was then glad I carried it along.

That memory might suggest that just because you take 3 or more lenses on the plane with you doesn't mean you need to carry them all, all the time. Depending on your daily itinerary, you can choose what lens to put on the camera and a single lens for the bag just in case, and lock the others in your suitcase. Have a good trip.

I have the same camera and lenses and travel a lot for work and pleasure. Always bring my trusty D750. Here's what I would do:

-Re: lenses... take the 24-70 for daytime and the 50 for walking around at night. You won't have any regrets. To be honest, for daytime shooting, the 24-85 f/3.5-4.5 VR would be a good option if you want to buy another lens before leaving. They're cheaper, lighter, and sharp enough. That and a 50mm and you'd be set.

-Re: precautions... pick pocketing and theft can be a problem, esp. in Paris. Here's what I'd do: I'd get a Peak Design Everyday Sling 10L. It easily fits my own D750 with a 24-70 attached and a 50, plus sunglasses and other things. You can sling it to the front of you for security, put it on your back when you're in a more secure area, and it's easy to keep track of when you're sitting at a cafe or restaurant. I tell all my students when I bring them abroad: put a little cash in the left front jeans pocket. Right front pocket keep a credit card and ID. Don't bring your debit card out with you, just use it to get cash in a cash machine and return it to your hotel with your passport. Your local driver's license will work fine as ID in Europe. Your wife should have a purse or fanny pack that can be worn across the body and in front of her, just like the sling.

Have fun! Don't load up with gear!