Context : Microquasars are potential \gamma -ray emitters .
Indications of transient episodes of \gamma -ray emission were recently reported in at least two systems : Cyg X-1 and Cyg X-3 .
The identification of additional \gamma -ray-emitting microquasars is required to better understand how \gamma -ray emission can be produced in these systems .

Aims : Theoretical models have predicted very high-energy ( VHE ) \gamma -ray emission from microquasars during periods of transient outburst .
Observations reported herein were undertaken with the objective of observing a broadband flaring event in the \gamma -ray and X-ray bands .

Methods : Contemporaneous observations of three microquasars , GRS 1915+105 , Circinus X-1 , and V4641 Sgr , were obtained using the High Energy Spectroscopic System ( H.E.S.S . )
telescope array and the Rossi X-ray Timing Explorer ( RXTE ) satellite .
X-ray analyses for each microquasar were performed and VHE \gamma -ray upper limits from contemporaneous H.E.S.S .
observations were derived .

Results : No significant \gamma -ray signal has been detected in any of the three systems .
The integral \gamma -ray photon flux at the observational epochs is constrained to be I ( > 560 { GeV } ) < 7.3 \times 10 ^ { -13 } cm ^ { -2 } s ^ { -1 } , I ( > 560 { GeV } ) < 1.2 \times 10 ^ { -12 } cm ^ { -2 } s ^ { -1 } , and I ( > 240 { GeV } ) < 4.5 \times 10 ^ { -12 } cm ^ { -2 } s ^ { -1 } for GRS 1915+105 , Circinus X-1 , and V4641 Sgr , respectively .

Conclusions : The \gamma -ray upper limits obtained using H.E.S.S .
are examined in the context of previous Cherenkov telescope observations of microquasars .
The effect of intrinsic absorption is modelled for each target and found to have negligible impact on the flux of escaping \gamma -rays .
When combined with the X-ray behaviour observed using RXTE , the derived results indicate that if detectable VHE \gamma -ray emission from microquasars is commonplace , then it is likely to be highly transient .