The visions of the prophet were shown to him as images and symbols which he interpreted to the best of his 16th century abilities and means. Thus, receiving the vision of a spiritual being surrounded by a great light, Nostradamus could not but recognize in that person a majesty and a wisdom that was way beyond that of the physical world. And this is why he adresses him as Serenissime Majesté [Most Serene Highness.]

Just as it was proclaimed A king will be born..., it is now proclaimed A child will be born.... No temporal king. No crowning. Simply the birth of a human being and his ultimate mission into the world.
The title Epistle to Henry, King of France Second gives us the first clue concerning the place of birth of the individual in question and it is, on the part of the prophet, an astute way to veil a clue which is quite important to the study in question.
First, I believe that France Second is a diverted way to give the land of birth. Of course, Henry II was king of France when Nostradamus wrote the prophecies and the designation King of France Second applies to him as he was the second of the name to be crowned king of France. However, the reference is so obvious and direct that Nostradamus could have simply writen Henry II.
So there is a hidden clue that can be retraced in the annals of Jacques-Cartier: on a second trip he made in 1935 [thus in the times of Nostradamus] the french navigator took possession of the New France [the Eastern part of Canada] in the name of Francois I, predecessor of Henry II on the throne of France. Thus the land having become a Second France to the people of France, the name king of France Second is a clear enough indication that the birth occurred in that part of Canada called Quebec and not in France as some may have suggested.
Another extract of the same Epistle narrows even more the search and gives us an astronomical configuration of the place of birth:
Then the great empire of the Antichrist will begin in the Atila and Zerses to come down in great and innumerable number, so that the coming of the Holy Ghost proceeding from the 48th degree, will transmigrate, chasing out the terrible antichrist.
Here, the word transmigration has two meanings. The first is the change of location [from a country to another], and it also indicates a radical change in the personage himself. This last excerpt is extremely important as it reinforces quatrains I-50 and III-35 interpreted below, and limits our field of research to a specific location of Canada. When it comes to astronomical configurations, one must take into account that there exists two spherical coordinates of the various points located at the surface of the earth:
the latitude, which is the angular distance of a place on the earth's surface from the equator as measured in degrees, the equator being latitude 0, the poles latitude 90, north or south, and the longitude, the angular distance between the meridian passing through a given point on earth's surface and the poles. Its is measured in degrees, east or west of Greenwich, which represents O longitude. [New Webster's]
The sentence itself may give us a clue as to which coordinate applies here: the coming of the Holy Spirit, proceeding from the 48th degree , is quite obviously an allusion to the Holy Spirit coming down on the Apostles. This Holy Spirit was considered by christianity as coming 'from above', and we have here the indication of a vertical configuration, a 48 degrees latitude. Thus, this 48 degrees latitude extending, horizontally to a great surface of Canada, we still need a few more clues to reinforce the theory of a birth on Canadian soil.
Another clue, found once again in the book of Maurice Poulin may reinforce even more the theory of a birth, this time on Quebec soil: on page 119 he quotes the Nostradamus Almanach:
Mais devers un côté [auteur: les 'Hespéries'] ubi hordeum potius quam frumentum nascitur. Aucuns Babyloniques & Égyptiens experts au jugement des astres luy ont présagé monarchiam, imperium sine fine dedit...
[But in that part [author' les Hespéries] where barley is grown preferably to wheat, there will be a birth. Many egyptian and babilonian astrologers have predicted monarchy, autority and unlimited power.]
The author links the words 'les Hespéries' to Canada, and concludes that the place in question is the province of Quebec, where 'barley is grown, preferably to wheat', mostly grown in the western part of Canada. The mention of Canada is an extrapolation of the author [M. Poulin]. However, my own search having its limitations, I cannot confirm nor deny his findings, and therefore will not comment on this excerpt.
All these signs are indicative but not sufficient to determine a more precise location. Thus we must turn to the quatrains and try to see if some of them could corroborate or reinforce the clues I just mentioned.
To this end, many quatrains seem to dissociate from the others by their clarity, indicating not only the continent, but the immediate environment where that birth took place, and may be, but very subtly, the name that person has chosen in the present life.
The interpretation will be fragmentary, in the sense that I am aware of the fact these few lines are but a smal part of the quatrains consecrated to this personage in the Centuries.