In a jar with a tight-fitting lid, combine the lemon juice, oil, sugar, onion, garlic, salt and paprika; shake well. Refrigerate for at least 1 hour.
Place broccoli in a steamer basket over 1 in. on boiling water in a large kettle or Dutch oven. Cover and steam for 8-10 minutes or until crisp-tender. Transfer broccoli to a serving dish. Shake lemon dressing and pour over broccoli; toss to coat.