This effect is most likely created in-camera rather than in post-processing. Based on the answers, the most plausible method is to use a long exposure and deliberately defocus the lens near the end of the exposure. That gives you a normal sharp rendering for most of the exposure, then overlays large out-of-focus light circles (bokeh-like halos) from the final moment.

A simple way to try it:

• Use manual focus.
• Set a multi-second exposure, such as 4 seconds.
• Keep focus correct for most of the exposure.
• Near the end, quickly rotate the focus ring far out of focus.

Because bright point lights bloom strongly when out of focus, you can get those circular halos while the buildings remain relatively sharp from the earlier part of the exposure.

Another possible in-camera approach mentioned is a fog/diffusion filter, or even a smeared front filter, which can create glowing light halos. However, the sharp-plus-halo combination is better explained by the long-exposure defocus technique.