OVH, SIP account (VOIP), Cisco SPA112 and CSipSimple

I have a SIP account (SIP is a protocol for voice-over-internet-protocol – VoIP) at OVH (a web hosting provider). I could choose, when creating the line, between various “national” numbers (France, Belgium, etc). I choose a french number (even though I live in Belgium), since nowadays most internet providers in …