I get it. I don't wear sneakers either other than at the gym. When traveling to Europe, I usually bring casual, comfy, cute sandals for walking during the day. I bring a second pair of shoes for dinner which are usually platform wedges. I like to pack dresses. I wear a fresh dress for dinner with my heels. The next day, I wear the dress worn at dinner the previous night with my sandals. All shoes are a neutral color. When looking for which wedges to bring, try to find something with a wider heel base as they are more stable for cobblestone streets. I also recommend rocking on the back heels to get a better sense of how stable they are. I recommend the platforms because if there are puddles on the street, the platform usually gives you the clearance needed so that your toes don't get wet.
I'll be traveling about the same time that you are and am a bit concerned about the cooler weather. I'm trying to focus on finding something in a muted gold metallic as I think it will be versatile. As my daughter tells me, sneakers are actually very trendy now. She actually wears white converse with a black dress and somehow it works. I'm actually thinking of getting a pair of Cole Haan Pinch Weekenders in metallic gold as I think that they will be stylish and dress up my capris. The other thing that I'm going to look for are flatforms. These are basically sandals that have a flat platform ranging 1"-3".
Espadrilles are a lovely idea. My only hesitation is if it rains the jute covering on the base may get discolored by dirt. But something along those lines may work if the shoe has over all stability. Again, rock on the back heels to test.
As a last resort, if you are traveling with a male companion, you can always take his arm as you stroll around as an added safety net.
Lastly, if you find a winner of a travel shoe, when you get back, buy three more for future trips. You won't regret it.
But above all, the shoes need to be comfortable, heel or no heel...