By request only - The TAG Heuer museum, inside the brand's HQ, is great. While quite compact compared to some other brand museums, it cleverly takes you through the journey of the brand around a 360 concept that reproduces the structure of a watch. 

There are some very neat pieces there, including one of the Monaco watches used by Steve McQueen on the shooting of Le Mans. 

However, it is important to note the museum is not open to the public by default: you have to contact the brand directly (details below) and request a visit, which is typically reserved for TAG Heuer collectors / customers.

Location

Rue Louis-J.-Chevrolet 6A - 2300 La Chaux-de-Fonds (Google Maps)

Open Hours 

Weekdays only, by request. Best way to channel the request is probably via your local TAG Heuer retailer if you have one, or by calling them directly on +4132 919 9000.

SWE Rating: Very good (would be "Excellent" but the process required to visit makes it harder than other museums).

How much? Free

SWE fun fact: The museum is almost hidden behind an automated door right behind the reception desk. It's very impressive when they let you in, and feels almost James Bond-esque (yes, wrong brand, but still!).