A little in-camera multiple exposure.
One shot ISO 1600, f/11, 30 seconds for the night sights. One shot 1/200, f/11 with flash (can't remember the power off the top of my head) for the rest. Just a bit of standard adjustments in LR, contrast, NR, sharpness, plus de-saturation of blues as my backdrop can sometimes turn a bit blue under flash lighting.
I'm sure I could have done this with one long exposure + flash but I had never used the multiple exposure feature of my 5D3 and wanted to play with it a bit