The 31-year-old touched down in Perpignan in November after his previous club Wasps went into administration and were kicked out of the top-flight English Premiership.
Shields soon nailed down a regular starting spot at Perpignan, who currently sit 13th in the Top 14.
The transfer marks a return to his roots, as Shields turned out for the Wellington-based Hurricanes between 2012 and 2018.