Assuming you mean Rue Montmartre the Paris transport route planner at
http://www.ratp.fr/ suggests the quickest route is to take the Number 13 train at Port de Saint Ouen heading south towards Chatillion 3 stops to Place de Clichy then take the Number 74 bus heading towards Hotel de Ville which travels down Rue Montmartre. If you're going to be making a number of journeys in Paris it's cheapest to buy a Carnet of ten tickets which can be used on both the Metro and bus systems.