There are three important things to note about this demolition:

1. The roofline decelerates (negative acceleration) when the upper block meets the lower block, indicating that the lower structure is providing resistance
2. The upper block is destroyed just like the lower block, demonstrating Newton's third law
3. There are no explosives used, so there are no big "bangs" (Popular Mechanics, NIST)

All three of these aspects are generally considered impossible by debunkers.

Bazant claims that the upper block of the WTC could be seen as a coherent "block of mass" accelerating all the way down, crushing the ever thicker and sturdier lower structure. This block of mass gives the illusion that somehow Newton's third law "does not apply" (see second point) to falling buildings, something dr. Greening was caught claiming.

The columns of the WTC were progressively thicker going down, making Bazant's model, the intact upper block of mass and the continued acceleration downwards at 0.6~0.7G (positive acceleration, see above, first in the list) extremely unlikely.

The last point shows that while there were many large explosions heard before and during the WTC's destruction, it's not an absolute prerequisite for building demolition. Furthermore, nano-thermite can be tuned for energy release, including sound energy, with what DoD apparently calls "impulse management". Note that Bazant explains away the explosions heard in the Naudet video as "sonic booms", using a formula with a variable that can be tweaked to Bazant's liking in order to prove his theory.

James Gourley challenged Bazant's theory in 2008 in the Journal of Engineering Mechanics (JEM). Bazant was subsequently given preferential treatment by JEM.

It is also important to note that Bazant seems to claim there is negligible to no loss of mass from the upper block as it accelerates downwards. This FEMA illustration shows how ridiculous that is, considering the explosive nature of the destruction of the WTC:

Even if that debris comes from below the upper block, that still means mass lost that cannot accumulate to increase the mass of the upper block and aid in crushing the lower structure.

To make a long story short: Balzac Vitry is a standing (pun intended) refutation of Bazant's semi-official "collapse" theory.

ETA: Here are some photos of the Balzac Vitry demolition.

What, weren't explosives used in this demolition at all?

Afaik not.

I quote:

Les verons hydrauliques, commandés à distance ont mis en mouvement la partie supérieure de l'immeuble, qui en se déplaçant latéralement s'est éffondré sur la partie inférieure.

I believe this says (In French) that some sort of remotely controlled hydraulic presses were used to displace the upper block laterally and thereby dumping it onto the lower block. French 911bloggers, feel free to jump in here...

A detailed discussion regarding the demolition of the Balzac Vitry was debated here .

Tony Szamboti commented on the differences:

"The abc tower was a publicly announced controlled demolition and two stories were removed to allow the upper block to fall at near freefall speed onto the lower block. WTC 7 had a freefall for 2.25 seconds or six stories and then there where jolts. The likelihood of that freefall occurring without columns being removed is extremely remote and so the reality that WTC 7 was a controlled demolition is highly probable."

"It isn't just reduced acceleration in the abc tower, although that does occur after the first two story fall probably due to the loose debris of the demolished floors, there was a real 15 to 20% velocity loss after the third story of the fall. This would have been when the upper block impacted the intact lower block. In the terms you would like to use, that means there was negative acceleration. It is quite unambiguous also, as it takes time for the velocity to recover and the velocity drop can be detected with more than one data point. Measure it and see for yourself."

"In WTC 1 the energy requirements to buckle the columns on the 97th and 99th floors would have drained 85% of the pre-impact velocity and conservation of momentum in picking up the 98th floor slab would have reduced it further. It would have been a dramatic velocity loss if there was an impulse after a 12 foot drop. There would then have been about a 1000 millisecond window to detect the velocity loss while it was recovering to pre-impact levels. But we don't see this velocity loss in WTC 1, therefore there was no negative acceleration, which means no force amplification and no natural mechanism for collapse. There is no way around that and that is why Dr. Bazant thought there had to be an impact and velocity loss or negative acceleration."

Dr. Greening: "The jolt is there!"