The Renaissance Republique is a good award-redemption value and its location is 15–20 minutes, by foot, from most Paris sights. I wouldn't pay $400 cash for other properties, if only because the savings can be spent on a good bottle of French wine and a nice dinner.

Of course, others prefer the Westin; the Prince de Galles, Luxury Collection; and other properties, but most of those preferences are based on elite status and upgrades on award stays. If it's a cash stay, I'd stay at the cheapest property with a good room and reasonably decent location. I suspect you'll be outside exploring for much of the day.

Maybe Le Dokhan's, Tribute Portfolio is worth considering.

You should definitely check each and every property to see if there are any member rates worth booking instead of the general rates. I'm willing to bet that there are rates that include breakfast or something.

If I do a dummy search on Marriott.com for 11–15 February 2019, I see the Renaissance Republique has a members rate of 265 euros per night, including breakfast, for a "larger room" with a queen-sized bed. Since you won't get breakfast as a Marriott gold that's a good value. Meanwhile, the Westin has a rate of 288 euros per night for a king-sized room for the same dates without breakfast included. The Marriott Opera Ambassador is 226 euros per night, including breakfast, for a king, queen or twin room. At the Marriott Champs Elysees, breakfast is included with a rate of 278 euros per night for a king or queen room.

So, basically, you have a lot of options for hotels and rates. It would definitely pay to search each property.