No wooden beam around your pétanque area?
No concrete slab to fix your bracket to the ground?
Here is an inexpensive and quick solution to implement it !
All you need is a concrete curb that you can find at all materials stores for a cost varying between 10 and 20 € per linear meter.
Choose the face with the most suitable width for fixing the bracket.
Bury the border flush with the ground with the side you have chosen towards the sky and quite horizontal.
Once the soil has been replaced and compacted all around, you can drill the border to fix your bracket using dowels and screws.