Jackets in the Summer

I arrived to Paris almost a month prior to show presentations. Coming here from Miami Fl., I was very well into the mindset of hot Summer days. I was shocked when I arrived in Paris and I had to put away all shorts and pull out jackets & pants. After viewing collections on last week I was confused at the amount of outerwear shown on the runways. I now understand that Europe's Summer start much later than they do in the US. So if you plan on being in these parts before July a nice jacket is a must. I'm still a bit schocked about all the leather seen though.