In contrast, I know that in the EU, architects have copyright on their work, which means you can't photograph the Eiffel Tower at night and share the photo, legally, without consent [2]
As to how you know if your photo is being used commercially...obviously there isn't a push-notification service (yet) that sends an alert to your inbox. You would just have to notice the commercial usage, as what happened when the teenager who was captured in a CC-licensed photo on Flickr found herself in a Virgin Mobile campaign
[0] https://www.cnet.com/news/google-begins-blurring-faces-in-st... (warning, autoplay video)
[1] https://www.youtube.com/watch?v=Vb3IMTJjzfo
http://www.thefrisky.com/2009-07-15/how-sacha-baron-cohen-ke...
[2] http://www.politico.eu/article/banned-taking-pictures-of-the...