The only non-French team left in the tournament, after Pontypridd, Munster and Llanelli fell by the wayside in the weekend quarter-finals, Ulster play the French champions on the weekend of 9-10 January.
Having beaten Toulouse twice, Ebbw Vale and drawn with Edinburgh Reivers at Ravenhill this season, Ulster will be pleased to have been drawn at home.
But the Irish provincial team might have to switch the game to another ground to meet the criteria for the semi-finals. The organisers have asked for a ground capacity of 20,000 for the two games.
After beating Toulouse 15-13 on Friday night Ulster officials were considering cutting down trees and moving marquees in order to increase their current capacity from 12,000.
Windsor Park, which has a capacity of 25,000, is one option in Belfast, Lansdowne Road, Dublin, is another. Should Ulster win, then Dublin would be high on the list of venues for the final, given that last year it was staged in France.
The Welsh referee, Nigel Whitehouse, had to have a police escort as he left the field at Colomiers' Stade Selery yesterday following a bitter second half in which he issued three yellow cards.
Despite a spirited effort from their pack, the Irish champions, Munster, were unable to follow in the footsteps of Ulster in beating French opposition. Down by 14 points at the interval after being hit by two early tries, the final deficit was 23-9.
Back row men Stephane Peysson and Bernard De Giusti grabbed the tries for the home team, while Munster had to rely on three penalties from the boot of Killian Keane for their points.
The Colomiers prop Stephane Delpuech and the replacement scrum-half Frederic Pedoussaut were given yellow cards by Mr Whitehouse, as was Munster's Des Clohessy.
The Welsh clubs were also unable to follow on from Ulster's dramatic lead in the European Cup quarter-finals as both Pontypridd and Llanelli found their French opponents too hot to handle on Saturday.
The Pontypridd captain, Neil Jenkins, was had no doubt about what went wrong in the record 71-14 hammering in Paris against Ulster's challengers, Stade Francais.
"The simple truth is that we were just not good enough. To lose by 70 points is shattering, but we simply haven't got the fire-power they had," said Jenkins nursing an injured shoulder.
EUROPEAN CUP Semi-finals Colomiers v Perpignan; Ulster v Stade Francais. (Matches to be played on weekend of January 9/10).
EUROPEAN SHIELD Semi-Finals Bourgoin v Brive; Montferrand v Narbonne. (Matches to be played on weekend of January 9/10).