thx, well all about this lens' flaws has been well summarized dozen of times ( lack of sharpness wide open + flare problem )
I really don't care about these defects since the 35mm summilux delivers a really unique character, and i'm not a sharpness addict ( use Rodinal , a good enlarger and you will get stunning b&w pics on FB paper )
here is an example of the flare problem ( pics were taken on Pont Alexandre III where there are lot of street lamps, so it's quite normal )