Sharing meals

Frowned upon or gauche, take your pick. :) it's just not done.

There's no requirement to each eat 2 or 3 courses. My husband often ordered a main and dessert, while I'd have a starter and main. Or we'd not be that hungry and just have mains. The portions are typically much smaller and easily eaten by one person. That said, there have been places where I'd have a few bites of his dessert or I'd offer him a bite/taste of my main course or starter or vice versa, but we've never formally split a meal.
We come away from meals feeling pleasantly satisfied, not stuffed to the gills.

One of my favorite things on this trip was the cafe gourmandise, a cup of espresso and a few tiny desserts all served at the same time. That, combined with the main course was a terrific dinner.

You probably won't be allowed to do it if ordering a prix fix menu. Of course one can always share a bite or switch plates, but two people ordering one menu meal isn't really appropriate.

If ordering ala carte, things are much less formal.

And eating at a bistro or café and sharing a plate there will be much more ok than doing so at a more traditional dinner restaurant. Keep in mind that for traditional restaurants, they do not expect or desire to "turn tables." They price their menu with the understanding that the diners will each order and enjoy the meal for the evening.

And as noted above, the plate portions are sooooooo much different than in the US. You may find their portion sizes much more to your liking.

We do it everywhere we go - sometimes we will split an appy sometimes we get two. We split a salad, entree & dessert. There is no way we could each eat two full meals and taking leftovers is just not possible. We did NOT share wine!

We were never treated any differently nor frowned upon nor told no we could not do it. Meals were always graciously served - some places would split the meal in the kitchen and we would be brought two plates and some would just bring us an extra plate to split ourselves.

We do not order a prix fixe meal.

"Frowned upon or gauche, take your pick. :) it's just not done. "

I totally agree with Zeeba. Just because a particular restaurant allows it doesn't mean it's appropriate.

As Douglas said, if it's a cafe, then that's different. But anywhere that has a table cloth and has a restaurant feel, then no.