There is frequently accent issues when developper is not european while most languages has accents. It is a question of character code. Normally all tables in the sql data base should be utf-8.
I solved the problem by not using Excel to open the csv files. IMHO Excel does not allow to select coding at csv file opening.
So you should use Open Office Calc, open it first.
Open the CSV file from Calc, it will recognise CSV and offer you to select character coding. Mine is utf-8 as I converted the SQL tables. Select yours. To know what's your go to you SQL base with Phpadmin.