Communion of the faithful. Notice the interesting two communion rails? This is sometimes seen in the north (as during High Mass the faithful wouldn't receive Holy Communion or would receive from a side altar to the right or left). For this reason they receive here from a portable wood rail with a linen veil atop it.
N.B. The faithful, when they receive Holy Communion, ought to keep their folded hands down under the veil and not atop the rail as seen here.