Plunge into the narrow streets of the St-Severin quarter to the east (rue St-Severin, rue de la Harpe, and rue Galande).
There are only super highways in St-Severin quarter.  
mnli hypothesis: There are only super highways in St-Severin quarter.   premise: Plunge into the narrow streets of the St-Severin quarter to the east (rue St-Severin, rue de la Harpe, and rue Galande).