I don't mean that it would be evident, definitely not in the way you could 'count the times' something would happen. That's not how I would describe systematic integration issues.
I lived in France for quite some time with near fluent French and it was nary impossible for met to break into French circles. I made basically zero French friends, most of my colleagues were ex-pats. And it's not like I was ever remotely 'mistreated', nor could I pinpoint any specific time wherein I was 'left out' or 'ignored' because I wasn't French but there was obviously some kind of invisible barrier. My girlfriend at the time, much like you, was born and raised French, but has Polish ancestry, and though, like you I don't recall her ever mentioning a single 'incident' ... it was clear she wasn't quite in the same group as the others. The demarcation was subtle, but to me it was there.
In Germany, where I lived for a year and barely speak a word of German, I felt as though my German surname gave me special access, as though I was 'a lost child', it's like I wasn't really 'foreign' just happened to be raised elsewhere - whereas the demarcation of Polish people (and especially Turks) was evident. Just like even in urban North America where you might see tables in a restaurant (or neighbourhoods) occupied by different groups (i.e. a very Asian table, a very white table), I found in Germany you'd see heavy demarcations as well, but more subtle: a table of Germans, a table of Polish/Germans, a table of Turks. Those divisions basically amount to barriers of a kind, because they will exist everywhere, at the office as well.
I lived in France for quite some time with near fluent French and it was nary impossible for met to break into French circles. I made basically zero French friends, most of my colleagues were ex-pats. And it's not like I was ever remotely 'mistreated', nor could I pinpoint any specific time wherein I was 'left out' or 'ignored' because I wasn't French but there was obviously some kind of invisible barrier. My girlfriend at the time, much like you, was born and raised French, but has Polish ancestry, and though, like you I don't recall her ever mentioning a single 'incident' ... it was clear she wasn't quite in the same group as the others. The demarcation was subtle, but to me it was there.
In Germany, where I lived for a year and barely speak a word of German, I felt as though my German surname gave me special access, as though I was 'a lost child', it's like I wasn't really 'foreign' just happened to be raised elsewhere - whereas the demarcation of Polish people (and especially Turks) was evident. Just like even in urban North America where you might see tables in a restaurant (or neighbourhoods) occupied by different groups (i.e. a very Asian table, a very white table), I found in Germany you'd see heavy demarcations as well, but more subtle: a table of Germans, a table of Polish/Germans, a table of Turks. Those divisions basically amount to barriers of a kind, because they will exist everywhere, at the office as well.