I saw the sign in the image on a fence surrounding someone’s house; it’s telling us not to leave our bikes locked après la clôture, or on the fence.
On the OQLF website, we’re given quite a few example sentences using this colloquial use of après. The reason they’ve provided the examples though is to suggest ways of revising them so as to avoid using après in this sense, which they tell us is inappropriate in formal language, especially writing.
We won’t look at their suggested revisions here, just a few of the original example sentences they’ve provided using après. If you want to see their reworded sentences, you’ll find that here.
In all the examples that follow, après is used where English might say on, in, at, with… Don’t worry so much about the English wording; just try to perceive what it is that makes it possible to say après in all these French examples.
La petite Caroline aime beaucoup grimper après les arbres.
The little (girl called) Caroline likes to climb trees.
J’ai dit aux enfants de ne jamais laisser la clé après la porte.
I told the children to never leave the key in the door.
Tu devrais te changer : il y a une tache après ton pantalon.
You should go change (your clothes): there’s a stain on your pants.
Elle a dû se retenir de ne pas crier après ceux qui l’avaient trahie.
She had to restrain herself from yelling at those who’d betrayed her.
Il sentait que David était furieux après lui.
He felt that David was furious with him.
Nous avons attendu après Jules pendant deux heures.
We waited for Jules for two hours.
Here’s a summary of all these examples using après for you to learn to recognise:
1. ne pas mettre son vélo après la clôture
to not put your bike on the fence
2. grimper après les arbres
to climb trees
3. laisser la clé après la porte
to leave the key in the door
4. une tache après son pantalon
a stain on one’s pants
5. crier après quelqu’un
to yell at someone
6. être furieux après quelqu’un
to be furious with someone
7. attendre après quelqu’un
to wait for someone
For the example sentence nous avons attendu après Jules pendant deux heures, maybe you’ll remember that colloquial language largely prefers on to nous. If this example had come up in a real conversation, nous avons attendu would’ve much more likely been said as on a attendu.