Jean Noël Hallé and the odours of Paris.

Perhaps fortunately, we are not yet able to recreate virtually the odours of historic cities.  By way of consolation, you can find on the internet, the full text of Alain Corbin's classic study of smells and their perception, The Foul and the fragrant: odour and the French social imagination (original French ed. 1982)   In the opening pages of his book Alain Corbin relates how he was inspired by the memoirs of Jean-Noël Hallé, first incumbent of the chair of public hygiene established in Paris in 1794.  In the early years of the Revolution Hallé was commissioned by the Royal Society of Medicine to undertake a  sanitary survey of Paris in order to investigate its noxious smells, which were thought at the time to be a direct cause of disease.

Jean-Noël Hallé,
http://www.biusante.parisdescartes.fr/
histmed/image?CIPB1002

The episode recounted by Corbin takes place on 14th February 1790, just over six months after the storming of the Bastille.  Hallé and his friend Boncerf set out in the early morning on a ten kilometre  round- trip along the banks of the Seine, equipped only with a map and their noses.  It is a mild day, with a southeasterly breeze and, near the Pont de la Tourelle, the river reaches a level of five feet. They begin at the Pont Neuf, in the heart of Paris, and continue along the Right Bank as far as the quai de la Rapée. Here they cross the river  almost opposite the sewer of the Salpêtrière, then  retrace their steps on the Left Bank.  Hallé's survey ignores everything other than odours, and concentrates exclusively on unpleasant smells which threaten to carry disease.

The sanitary survey is not without its dangers.  On this occasion Hallé's companion Boncerf, while facing the breeze and wading along the edge of the black mud of the notorious Gobelin tributary, finds himself overcome by noxious fumes:  

Monsieur Boncerf, who at this point had turned more directly into the south-easterly breeze and had descended to the riverbank, was overcome by a biting, alkaline, stinging, and stinking odour.  It affected his respiratory system so badly that his throat began to hurt within half an hour and his tongue became noticeably swollen.  Affected by these poisonous vapours, he warned me to return to the road straightaway;  because I had remained at the easternmost point of the bank that had been infested by these sediments, and hence with my back to the wind, I myself did not experience anything unpleasant.
(Hallé, "Procès-verbal", p.lxxxvi)

In this extract from the TV documentary Filthy Cities, introduced by Dan Snow, historian Andrew Hussey retraces  Hallé and Boncerf's route.  Andrew Hussey concludes that Hallé's findings were truly revolutionary;  it was Hallé who for the first time clearly differentiated  smells which were merely unpleasant from those which were truly noxious, in this case the poisonous fumes produced by the tanneries and other industries of eastern Paris.

References

Alain Corbin,  The Foul and the fragrant: odour and the French social imagination
https://www.scribd.com/doc/215893024/Alain-Corbin-M-Kochan-The-Foul-and-the-Fragrant-Odour-and-the-French-Social-Imagination-Berg-Publishers-1986

Dan Snow Filty cities:  Revolutionary Paris (2011 TV series)
https://vimeo.com/23405739


Hallé's original account: 

J.-N. Hallé, "Procès-verbal de la visite faite le long des deux rives de la rivière Seine, depuis le pont-Neuf jusqu'à la Rappée et la Garre, le 14 fevrier 1790,"
Histoire et Mémoires de la Société Royale de Médecine, 10 (1789).  BIU Santé website
http://www.biusante.parisdescartes.fr/histoire/medica/resultats/?cote=05749x1797&p=101&do=page