Dear Sir or Madam,
I am writing to enquire about the possibility of carrying out a work
placement in your firm.
As a student of (matière) at (établissement) I am required to work for(ex: four weeks)as part of my course.I am of course happy to accept the fact that this work would be unpaid.
I am highly motivated for a work placement in your organisation because
I feel that I would be able to make a useful contribution and it would also
be an enriching experience for me.
Please find enclosed a copy of my curriculum vitae.
I am available for an interview at your convenience.
I look forward to hearing from you.