The game came to life in the 12th minute when Constantine Mika was sin-binned for a dangerous tackle on a Rams attacker, and Dewsbury took swift advantage as Robbie Ward darted over, with Paul Sykes converting.
Toulouse hit back when Dewsbury spilled possession on their next attack and Rhys Curran gathered a short pass to crash over. Mark Kheirallah converted to level.
With Dewsbury in a dangerous attacking position, scrum half Stan Robin intercepted a pass and raced 80 metres unopposed to score and Toulouse added two further converted tries before half-time through Tyla Hepi.
Dewsbury stunned the high fliers with two quickfire tries at the start of the second half, Dale Morton and Rob Spicer, Sykes’s conversion for the latter reducing the arreas to six points.
A Kheirallah and Tony Maurel try extended Toulouse’s lead to 28-16, but Dewsbury hit back when Michael Knowles dived over from acting half-back and Sykes converted.
Curran grabbed his second try and Kheirallah converted to give the visitors breathing space.
Toulouse grabbed a seventh try in the final minute when Kheirallah rounded off a long-range move to score between the posts and give himself an easy conversion, but the final scoreline was somewhat harsh on the Rams.
Dewsbury Rams: Guzdek; Simpson, Glover, Hallett, Morton; Sykes, Knowles; Sheriffe, Ward, Teanby, Crowther, Spicer, Brown. Substitutes: Speakman, Walshaw, English, Everett.
Toulouse Olympique: Kheirallah; Marcon, Planas, Ader, Maurel; Ford, Robin; Rapira, Marion, Canet, Mika, Curran, Bentley. Substitutes: Barthau, Boyer, Hepi, Sangare.
Referee: Jack Smith (RFL).