This paper deals with the motion planing in real-time for swarm of agents using distributed Model Predictive Control (DMPC). Optimization-based control helps both to stabilize the motion dynamics of the robots and to enforce the system's constraints. However, the price is a significant increase in complexity as the scale of the system surges. To improve the scalability for a large formation, we propose a DMPC framework that considers B-spline parameterizations for the agents' trajectories.