Genealogy is a true investigation into the history of one’s past. Schematically, you will follow, at least initially, the same traditional steps:
Inventory and collection of elements remaining in the family: both family papers (including family booklets, which have only existed since 1880, announcements, family photos, etc.) and family memory, which you will explore through numerous and exhaustive interviews, starting with the deans, a stage that you will end with a possible visit to the cemetery, to take down inscriptions (especially dates).
The first research: will often be carried out by correspondence, because the current French legislation which prohibits direct access to civil status documents dating from less than a hundred years. You will obtain a civil status certificate concerning the most distant ancestor on which you have information (generally your grandfather or your great-grandfather).
This act will most often be that of his death. You will ask for it at the town hall of the place of death, remembering to attach a stamped envelope with your names and addresses.
This death certificate will tell you where this ancestor was born and on what date, as well as his filiation (surname and first name of his father and mother). Since he was born in principle before 1922, it will be useless to go and see his birth certificate: before this date, in fact, birth certificates did not include the date and place of birth of the parents, but only their ages and occupations.
This is where everything gets complicated in genealogical research. You will have to go and consult yourself the civil status of more than one hundred years of the commune of birth to begin your research there.
Initiate the search on archives: in the civil status of the town of birth of your ancestor, you will first seek the marriage certificate of his parents (one time out of two, it will have been celebrated there). Help yourself for this with the ten-year alphabetical tables, grouping the marriages by periods of ten years.
Otherwise, look for, in order, the death certificate of the father, that of the mother, or any other clue to know where the parents could come from. On the other hand, avoid rushing to find the birth certificate. Jean Brincourt, residing in Chauny in 1882 and aged 32, was not necessarily born there. And even if a Jean Brincourt would have been born there, nothing will say that it is really about him (he can be a namesake or a cousin).
This is the case throughout the research: at each generation, you will have to bounce back from the elements found in the records to find one (marriage or death) delivering the previous generation to you. This is where you will have to be patient, logical and rigorous.
Please note: be aware that ages are often approximate (within 2 or 3 years) and that the spelling of surnames continued to change until the beginning of the 20th century. Don’t let yourself be confused by Dupont ancestors becoming Dupond, by Delaplaces becoming Laplaces or Lobgeois transformed into Lobligationois…
The civil register, created in 1793, once exhausted, you will work on the parish registers, gathering the acts of baptisms, marriages and burials, less and less rich in information as you go back over time.
You should be able to go back, on average, to the second half of the 17th century. In fact, everything depends on the richness and age of the archive collections, which can vary from one municipality to another.
Exceptions: certain situations may lead you to particular sources and different methods:
If you want to go back further, different tracks can be offered to you. The notarial archives include very old marriage contracts (formerly the rule in all circles).
Tax archives, old censuses and burrows can finally allow you to dive back to the 15th and 14th centuries, but most often without continuous filiation.
Knowing your ancestors and having their dates of birth is good: seeing them live again is better! The notarial and tax archives will help you to get to know them better on a social and economic level…