I finally answer my own question!
Here is a really good recipe for merguez
500g of lamb (boneless shoulder)
500g pork (boneless shoulder)
2 garlic clove mashed with olive oil
2 teaspoon cayenne
1 teaspoon of each cumin and coriender seeds grounded
1/2 teaspoon peppercorn grounded
Ground the meat then mix with the herbs. Fill the guts with the meat. Jam the sausages with a clean needle. It keep 2-3 days in the frig or freeze really well.