In Southern France, small slivers of a brown, salty, dense something was tossed with string beans. Was it a bouillon cube?

Thanks!!

It could have been bottarga (that's the Italian and best-known name, but it's called boutarge or poutarge in France)

Green beans love anchovies. They give a salty umami flavour. That would be my guess

I bet it is Maggi cubes, sliced! Going to try it. Can’t remember how salty it was, but it is a dead ringer for them. Just thinly sliced.

Could it have been Maggi cubes? I've seen them (and Maggi) used regularly in the average French home.

Caramelized shallots/onions? seasoned of course

My first thought was anchovies, Sometimes they get soaked in milk before using to remove the fishiness.
Lardons may be more likely, but they are nor usually "slivered," but left in tiny chunks.

I suspect they were lardons, which were minced. It's from the same belly cut we'd make bacon of, but it's not smoked. It might be closer to what we'd recognize as salt pork. At any rate, I don't think it would have been a bouillon cube, at least not in France. That would probably get the chef stripped of his/her French citizenship. You can do the same thing in the US using pancetta, or sometimes with bacon if you don't mind a smoky add in taste. Lardons are salted and cured, and some will be cold smoked. Pancetta is generally only salted and cured. You can use bacon or salt pork as a substitute, depending on if you wanted a smoky flavor or not. Salt pork would probably need to be soaked to remove excess salt, though you'd have to determine that yourself.