Yep, Ficus carica can be allelopathic.

Joe

Here is a link that might be useful: UCD study on Ficus carica allelopathy

Figs reseeding continues to mystify me. We bought this property 20 years ago with one fig growing in the orchard. We tasted the fruit and did not like it, we have no idea of its species, so I dug it out and planted a fig I do enjoy the fruit. Every year I find more fig seedlings growing hundreds of feet from the original tree. Seedlings even appear between rocks in retaining walls. These are all seedlings from the original fig long ago removed. Al

Sounds like you have a lot of happy birds

We have an old fig tree (50+ years?) that is gnarled and twisting and picturesque and productive (ask the squirrels). Though it has this age, new shoots (branches) grow quite profusely from one side at the base of the trunk every year. For years I would just hack them down to the ground as this growth was untidy. However when I noticed the main tree was aging I decided to cultivate certain of the sprouting branches so they would become thick and healthy and provide balance and new life to the tree. This is working out nicely.
As far as stuff not growing under or near fig trees, I can tell you that forget-me-not does in my yard. Oxalis does. The nasty wild onions do. California poppies do. These are all really weeds...I didn't place them there but they do grow there. I'm not sure why or what you would actually want to plant under a fig tree. Containers would be a better bet than the ground under a fig. Although...there is this caveat.
There are many containers under my fig tree holding either annual or perennial plants. Talk about baby fig trees sprouting in those containers from the fruit pieces the birds and squirrels drop! Incredible.

Which "fig" are you talking about? The edible-fruit kind or Ficus in general? Some ficus have huge root systems and nothing grows under or near them due to that.