To clarify, your boyfriend would not be applying for a working visa (officially an "Employment Visa", which are linked to specific jobs and which are sponsored by the employer) - he would be applying for a dependent visa, which would allow him to work anywhere and which would be sponsored by you.
To be honest my feeling is that it may be a struggle to get a job, but not impossible, particularly since your salary expectation is very reasonable.
If I were him I would start by applying to the HK offices of French or Belgian multinationals who might need software expertise here, emphasising that he would not need to be sponsored for an employment visa.
For example: Alcatel, CLSA, BNP, Fortis, SocGen, ... (the French Chamber site here
http://www.fccihk.com/ may be of use)