I am not a professional but would like to give some opinions:
First of all, it is a nice shot showing the glory of the Paris's icon and I like it. Here are my opinions:
(1) Are you using high ISO setting? Some cameras handle high ISO setting beautifully others are bad at it. Also, with night photography with lots of areas in shadows/complete darkness (i.e. black pixel with a zero value) it is hard to have effective noise control. Hence it is better off with a lower ISO setting.
(2) This relates to point (1) somewhat. With lower ISO - and if your camera allows setting of f-stop then one should set high f-stop numbers (eg f16 or f22), the restriction of these f-stop will show point light source as stars like lumination that I find pleasing to the eyes. Also with higher f-stop number you will need lower shutter speed (and hence tripod shoiuld be used) the moving vehicles will show up as lines of lights.
(3) The last point is that it is good to have shots taken just before the sky gets completely dark. With long exposure, the sesnor can pick up colours that our naked eyes cannot detect - and your shot will not have lots of complete darkness.
Having said all of these I must admit that i make these errors of judgement all the time and often realise them too late to make any corrections.
Cheers
