In a medium saucepan, bring the broth to a boil. Once boiling, stir in the couscous and remove from heat. Cover and let it sit for about 5 minutes until the couscous has absorbed the liquid. Fluff with a fork and set aside.
While the couscous is resting, heat olive oil in a large skillet over medium heat. Add minced garlic and sauté for about 1 minute until fragrant, being careful not to burn it.
Add the shrimp to the skillet, season with salt, pepper, paprika, and red pepper flakes, and cook for about 2-3 minutes per side, or until the shrimp are pink and opaque.
Zest and juice the lemon, then pour the juice and zest over the cooked shrimp. Toss until the shrimp are well coated.
In a large mixing bowl, combine the fluffed couscous with the shrimp mixture and chopped parsley. Stir well to combine all the flavors.
Taste and adjust seasoning if necessary. Serve warm, garnished with lemon slices and additional parsley if desired.