What are the dates of these panoramas of Paris?

Acknowledgement: this answer owes a debt to some of the comments posted under the question and under this answer, especially Kimchilover.

There is conclusive evidence that all three images are from after the 1789 revolution and strong evidence that at least one was made no later than 1834. However, there appears to be conflicting evidence on a more precise date if all three images were made around the same time. This confusion relates to the text at the bottom of the images and, if we accept that an error was made, the images can tentatively dated to the early 1830s.

FIRST PANORAMA

On the left, the nine-arch Pont des Arts gives an earliest date of 1802-1804, which was when this bridge was constructed.

The next item of interest is the area of Port des Saints Pères (Port des SS. Pères), but the Pont du Carrousel, begun in 1831 and inaugurated in 1834, is missing. This gives us a latest date of 1834 (but most likely earlier as there is no evidence of construction). Interestingly, the name 'Port des Saints Pères' was not used until mandated by a "décret préfectoral du 18 juillet 1905" (previously it was port du Recueillage, then port Malaquais) so the text at the bottom must have been added much later unless the name was in informal use before 1905. This increases the likelihood that errors were made (see Third Panorama for the potential relevance of this).

Minor dating evidence comes from the École de natation. This is mentioned in Nouveau manuel complet des nageurs, des baigneurs, des fabricants d'eaux minerales et des pedicures, published in 1838. The text in the book mentions it as L'ecole de natation pour les dames, au bas du quai Voltaire.

SECOND PANORAMA

There doesn't appear to be much to go on here other than the Arc de Triomphe (as pointed out by Spencer's comment). Begun in 1806, it took two years to complete the foundations and

in 1810 with the marriage of Napoleon and Archduchess Marie Louise von Hapsburg of Austria...A wood and painted canvas replica of the Arch was constructed the same as it was to be built.

There followed numerous delays as regimes changed and architects died or were removed. At what stage the panorama shows the Arc is impossible to determine - it was completed in 1836 but the main structure was probably in place sometime before then so the panorama could easily be from before then.

To summarize, the earliest possible date is 1810 (the replica), while the latest date is hard to determine.

THIRD PANORAMA

According to the text at the bottom of the Third Panorama, the Hotel des relations extérieures was under construction at the time this image was made. This gives a date of between 1844 and 1856. However, the building may have been misidentified and / or the writing en construction (under construction) may be a mistake (quite possible if it was added more than 50 years after the image was made, as suggested by the First Panorama, assuming the images are from approximately the same date).

Evidence for an earliest date comes from the Palais de la Légion d'Honneur, built between 1782 and 1787 but not called the Palais de la Légion d'Honneur until 1804 when it was nationalized by the revolutionary government.

A little further along is the Chambre des députés, the name of which was changed to the Corps législatif in 1852 so, unless the text writer was unaware of this change, the date can be no later than 1852.

On the far right, is the Pont Louis XVI, now known as the Pont de la Concorde, completed in 1791. The name Pont Loius XVI was used during the Bourbon Restoration (1814 to 1831) but, as it is not uncommon for renamed roads, bridges e.t.c. to be referred to by their previous names for quite some time after an official renaming, one cannot assume that the image dates from no later than 1831. In addition, there is the potential aforementioned problem that the text was added much later.

Finally, concerning Kimchilover's comment containing the link to Bance, fils et successeur de Bance Ainé: the OP's panoramas may well be three of the four mentioned in this 1831 volume. Unfortunately, without being able to confirm this, there is no way to be sure.