This animation show the process in 2 steps. The first one ("During") apply all the DxO Optics filters except the DxO Noise. The last step ("After") append the noise filter to smooth the picture.
One can notice in the crop that the Sharpness module enhance the noise, the picture looking more noisy than in the original photo. That normal, because the noise module thinks that the noise is the details. But once the DxO Noise applied, the noise virtually disappear.
The most impressive thing is the apparition of many stars inconspicuous before processing in the upper right corner.
Notice also the significant chromatism around Betelgeuse (the center crop) which disappear totaly after processing.

Canon 350D + Sigma 10-20 at 10 mm open at 4 on a tripod. 30 s at 800 ASA.

Notice: in the crops near the corners, the picture shift due to the DxO Optics Distortion option which flattened the photo.