Ragnar's move on Paris will kick off the largest battle yet. Vikings' season 3 raid on Paris will be big enough to require a bit of CGI. 'Vikings' Season 3: Bjorn Looks To Rollo For Advice? Clive Standen Teases Uncle/Nephew Relationship The new King of Denmark and his warriors will have their eyes on the French city during the second half of season 3, and their attack won't be something to scoff at.