I presume you meant from late medieval times to the end of the seventeenth century? France actually had very slow population growth by western standards in the second half of the nineteenth century (the withdrawal method - more effective then you'd think ;)In any case I don't believe fossil fuels were used in French farming in serious amounts until the twentieth century though I'd have to check to see if my memory is correct.
As to population growth in the 18th century, indeed it was smaller than in other European countries, but that is also because more land had already been filled by agriculture than in, say, Germany. Auferre, trucidare, rapere, falsis nominibus imperium; atque, ubi solitudinem faciunt, pacem appellant.
