Spent two nights at this place. Seems like the owners invest mainly in their restaurant and the accommodation is only an after-thought, and not a good one.
Main two problems are: (1) tiny rooms that feel old and worn-down, and (2) HORRIBLE levels of noise (if you pick a front facing room, it's above the restaurant with ongoing chatter and smells of food from lunch until late night; if you pick a back room, there's a dance club with beat music until around 3AM). We slept a minimal amount of hours and tried to stay away from the room during the day.
The location is right in the central market, however Haarlem is so compact that all other hotels will be near it anyways. Plus, this one is too central, as all the noise and dirt is right in you face.
We thought the staff were nice, breakfast alright (good coffee) and cleanliness levels fair, but that's all the positives.
I'd like to say that if this was priced cheaper it'd be worth the money, but not sure if even that's fair to say, as you really just don't sleep well there.
We were happy to move to our next stop (Amsterdam) and to a real hotel.

Had a short stay here over Easter weekend. Having arrived very late (just gone midnight) was relieved to find they had kept our room vacant! Despite the crowds in the square enjoying the unusually warm spring weather the room (21) was really quiet, other then the sound of the shared shower being used in the floor above. The rooms are basic, ours did have a tv and a small, tired, but clean bathroom (there are some rooms which do not have ensuite). Breakfast is basic but completely adequate with a selection of cereal, fresh fruit, yogurt, different breads, ham, cheese, egg and yes even a toaster!! The coffee is to die for (ie short and strong!) and the staff were always really friendly and helpful. There is also a lovely menu in the restaurant, the ribs especially highly recommended. Remember this is a "budget" hotel and you will definitely not be disappointed.

I should have twigged when the manager/owner insisted I paid the bill on my card before I stayed.
What an appalling stay. First night (room 11) in a less than 1 star room. Narrow bed, washbasin over the end of the bed so you had to use it from the side. Stairs so steep they were dangerous. 2nd night (room 24) having asked for a better room I was put into a room adjacent to a ( next to the party wall) student pub/club with heavy beat music all night till 4am. No sleep at all. The club even had loud music on whilst they did the post party cleaning up. Then an hour of clattering while they set up the outside chairs for the day. I'm so disgusted by thehotel and the manager/owner. I left after the 2nd night and found a real hotel nearby actually cheaper too. Do not ever stay there. How they got a certificate for hotel use I'm amazed! Someone ought to take it up with the Dutch Hotel Standards Organisation.

Do not ever pay a hotel bill before you've stayed there because it's not easy to complain
after they have the money!!!

I had stayed at the Carillon about 20 years ago. We booked it for a weekend 2 weeks ago. The restaurant downstairs is excellent and modern. The bar are is the same, excellent and modern. Superb staff of helpful people. Our rooms were #15 and #16 on the 1st floor. They were tastefully decorated and met all our needs. They were also very quiet. I recommend this Hotel to anyone seeking a nice, clean place to sleep in Haarlem/Amsterdam. It is so much cheaper than staying in Amsterdam, which is only 20 minutes away by train. I have already booked a return visit.