There are no single "best" cellist, but if you mean recognition, Emmanuelle Bertrand won the 2011 "Diapason d'or (Gold Diapason) - Artist of the Year" price, a competition organized by the national radio France Musique and the magazine Diapason.
There is also a list of French cellists on French wikipedia but this site does not allow me to mention their URLs, you need to search for it.
In French meilleur means best.
"Best" is "meilleur" (masculine) or "meilleure" (feminine) in French.
they were the best of the best and the french were not very good
'best by date' in french is 'mieux par date'
Best is meilleur (masc.) or meilleure (fem.) in French.
The best player is "le meilleur joueur" in French.
There is no best breed. The best French breed depends on what kind of qualities and characteristics you're looking for. The best french breed in terms of calving ease is Limousin, for instance.
you are the best is translated in French as "tu es le / la meilleur(e)"
You simply say "French is the best."
Best before - translates to French as "À consommer de préférence avant"
best memories
best friend is called "meilleur ami / meilleure amie" in French