As said, shaping figures are to be applied to outbound interfaces. So, i.e., should you need to limit the inbound/outbound BW of the internal host w.x.y.z, being your egress iface 'xl0' and your local iface 'em0', you would limit to 100Mbps traffic going to w.x.y.z through 'em0', and limit to 10Mbps traffic comming from w.x.y.z through 'xl0' (always outgoing flows).
Regards!
