The Routin syrup and the Petit Canne are different.
This is what is in Routin:
No preservatives: Flash pasteurised and homogenized
* No fat, No cholesterol
* The pure water from the French Alps
* Sucrose and Fructose
* Colour of natural extracts
* Fruit juices and plants
* A concentration of flavouring
While Petite Canne sugar cane syrup is made from pure cane sugar grown only on Martinique and captures the rich flavor of the sweet fresh cane.
Contents: Sugar cane syrup,
ascorbic acid for color retention and
potassium sorbate as a preservative.
It looks to me like Routin is more a coffee syrup than a syrup for cocktails.
But that doesn`t mean it can`t be used in cocktails or in a Ti Punch, but that Petit Canne and similar syrups are better for use in Ti punches than coffee syrups.
But maybe you should try to find Petit Canne and make a comparaison?
Or maybe make your own syrup?
Here is a
link to a thread in the White rums section where Ed explains about Petit Canne: