Experiment number one: international.com and international.com/fr
We imagined a situation where the english & international version of a website would be at the root domain let’s call it international.com since we can’t disclose the real domain name that we used for doing this experiment. Then, we created a french version at international.com/fr
We added international.com and international.com/fr to Google Search console and we discovered that for the google traffic of international.com also included the one from international.com/fr. For sure, the international.com/fr results only included results from international.com/fr
Experiment number 2: international.com and fr.international.com
In this case, in google search console, we discovered that international.com only included the results for international.com and fr.international.com included the results for fr.international.com only.
It is better to create a subdomain if you want one website in the root domain and another website somewhere else in order to track Google traffic.