Having the same issue in the opposite way, the best advice I have is to rely on Wikipedia’s interwiki, both for the style and for the vocabulary. Try to read the same proof in French and in English and to see how sentences and symbols map¹, if you need a translation of a word, look at the article in (en), then follow the interwiki to (fr). It works for almost everything².

I expect that you will get the structure fairly easily, as it is doesn’t change much between proofs. Just be aware that the philosophy of mathematics is not quite the same in France and in Anglo-Saxon countries. France remains under the influence of Bourbaki, whereas many Anglo-Saxon mathematicians now disregard this approach.

_{1. & 2. Haha}

Si l’ arithmétique vous intéresse, je vous recommande chaudement le petit livre de Pierre Samuel Théorie algébrique des nombres, publié chez Hermann.
Ce livre est un petit bijou ne nécessitant comme connaissances préalables (“prerequisites”) que les matières enseignées dans les deux premières années de l’université.
(Pour la petite histoire, il s’agit d’une version édulcorée d’un projet de rédaction pour un volume de Bourbaki qui finalement n’a jamais vu le jour.)
La cerise sur le gâteau est qu’il existe une traduction en anglais de cet ouvrage , également publiée chez Hermann, que vous pourrez utiliser en cas de difficulté.

Edit
Since Sabyasachi might not yet know enough French to understand my answer , let me say that the gist of it is that he might try to read Samuel’s elementary and beautifully written Théorie algébrique des nombres, published by Hermann, and that the icing on the cake is that there is an English translation ( same publisher) which will be helpful in case a problem with the language should arise.