REGIMENT VON RÜHLE (from the vicinity of Le Touquet to somewhat south of Frelinghien) was an ad-hoc formation commanded by Hauptmann Alexander Rühle von Lilienstern of IR 134. Its sector around the town of Frelinghien on the Lys was held by III. / IR 104 and II./ IR 134 on the northern and southern banks, respectively facing 2nd Lancashire Fusiliers (12th Brigade / 4th Division) and 2nd Royal Welsh Fusiliers (19th Brigade / 6th Division).
As noted above the Lancashire Fusiliers certainly fraternised on Christmas Day; according to their published history, 'A' Company played an impromptu game of football against the Saxons with an old tin. Events on the south bank are much more extensively documented on the British side, although as noted above the published history of IR 134 is highly reticent.
The Royal Welsh Fusiliers put up an improvised 'Christmas card' on a sheet of canvas on Christmas Eve, and when the fog cleared early in the afternoon of Christmas Day the Saxons began to call across to them. Captain Stockwell met his counterpart, "Count something or other" (possibly Hptm. Wilhelm Graf Vitzthum von Eckstädt of IR134) in No Man's Land, and beer from Frelinghien's Lutun Brewery was donated to the Welshmen in return for a plum pudding.
Hostilities were theoretically renewed on Boxing Day, but the sector remained quiet; the Welsh were relieved by 2nd Durham Light Infantry of 18th Brigade that evening.
Note: There were in fact two breweries in Frelinghien, both fortified by the Saxons. The one immediately behind the front lines of Regiment von Rühle was the Lutun Brewery, known to the Germans as the Südbrauerei. See Chapter 2 of For King and Kaiser for much, much more on the subject of the Frelinghien breweries and the events which took place there.
Above: Infantrymen of IR 134 in the trenches of the Frelinghien sector (probably southeast of the fortified Lutun Brewery) on 19th April 1915. Note how far the 'floor' of the 'trench' has had to be raised above the swampy ground and the enormous height of the sandbag barricade.