Since 2005, the workflow working group of OV-France gathers astronomers from five french institutes with common objectives: (i) defining use cases of general interest; (ii) identifying the simplest workflow structure allowing portability; and (iii) suggesting solutions for designing and exploiting easily such workflows (cf. Astrogrid developments). Our workflow definition is the following: a sequence of tasks executed within a controlled context by an architecture taking into account VO standards.